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Wastewater-based Disease Surveillance for Public Health Action (2023)

Chapter: 4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance

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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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4

Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance

This chapter addresses how the vision of a robust wastewater surveillance system described in Chapter 3 can be achieved. First, the committee describes a formal process that could be implemented to systematically and transparently evaluate potential targets for wastewater surveillance. Second, legal and ethical issues arising from wastewater surveillance are discussed. Although these concerns are not weighty enough to militate against the expansion of wastewater surveillance at the community level, the committee discusses the benefits of creating an ethics governance structure to consider the potential impacts of expanding the scope of data collection or data sharing. Third, the committee examines the steps needed to assure that wastewater data are reliable, representative, comparable, interpretable, and, therefore, actionable. Fourth, key elements of a sustainable system are examined, including operational capacity and financial dimensions, both of which may require substantial investments. Finally, the committee considers the collaboration and coordination necessary to support an integrated system and the respective roles of federal, state, and local participants in such a system.

A SYSTEMATIC AND DYNAMIC PROCESS FOR EVALUATING TARGETS FOR WASTEWATER SURVEILLANCE

The U.S. Centers for Disease Control and Prevention (CDC) has the important task of prioritizing among candidate pathogens or pathogenic markers to include in the National Wastewater Surveillance System (NWSS). The previous chapter described three substantive criteria for distinguishing

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

among potential candidates: public health significance of the threat, analytical feasibility, and usefulness of community-level wastewater surveillance data in informing public health action. In this section, the committee proposes a strategy to apply those criteria, including a formal process for generating an initial list of candidate pathogens, prioritizing among them for inclusion in the NWSS, and regularly updating both.

Development of (and updates to) a list of candidate pathogens should build on existing work, evaluating extant lists of candidates against the substantive criteria described in Chapter 3. Several groups already have strong infrastructures for identifying candidate pathogens, including but not limited to CDC; the National Academies of Sciences, Engineering, and Medicine’s Forum on Microbial Threats;1 local and state health agencies that issue reports about new infectious agents; and the World Health Organization’s Global Antimicrobial Resistance and Use Surveillance System (GLASS).2 Additionally, public health significance may be assessed by looking at clinical case and hospitalization data, treatment costs, availability and uptake of vaccines, and lists of antimicrobial resistance genes reported in clinical cases. Community wastewater surveillance targets may also be identified from concerns identified in other countries or pathogen outbreaks in highly localized settings, like hospitals.

CDC should develop and implement an open and transparent process by which potential targets for wastewater surveillance are evaluated according to key selection criteria. A useful analogue is the development of a “contaminant candidate list” (CCL) by the U.S. Environmental Protection Agency (EPA) for drinking water monitoring and regulation. The CCL is a list of contaminants that are known or anticipated to occur in the nation’s public drinking water systems but are not currently regulated under the Safe Drinking Water Act of 1974 (NRC, 2001). The CCL is mandatorily updated every 5 years and is used to prioritize contaminants for regulatory decisions. Although there are clear differences between the CCL and a list of agents that could be selected for wastewater surveillance, two aspects of the CCL development process have high salience for making determinations about agents to include in wastewater surveillance: the use of expressly defined criteria and procedures for obtaining public input. Notably, the substantive criteria applied by EPA in making regulatory determinations on contaminants from the CCL resemble the criteria described in Chapter 3 for wastewater surveillance: (1) the contaminant may have adverse human health effects, (2) “there is a substantial likelihood that the contaminant will occur in public water systems with a frequency and at levels of public

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1 See https://www.nationalacademies.org/our-work/forum-on-microbial-threats.

2 See https://www.who.int/initiatives/glass.

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

health concern,” and (3) regulation would provide a meaningful opportunity to reduce health risks.3

Based on the recommendations of the National Drinking Water Advisory Council (NDWAC, 2004) and the National Research Council (NRC, 2001), EPA began soliciting public nominations for unregulated contaminants for inclusion beginning with the third CCL. Similar to the development process for the CCL, CDC could solicit public comment on potential candidates for wastewater surveillance, making targeted outreach to the global academic community and experts from public health, industry, and utilities. To update the candidate list, this solicitation could be repeated at regular intervals (e.g., biannually, or more often during periods of disease outbreaks of public health significance). Once a list of potential targets is defined, the public could be further included through posting of requests for information on the agents and/or open public comment period on candidate targets.

From the potential candidate list, CDC will need to prioritize an initial suite of wastewater surveillance targets. In so doing, CDC would benefit from creating a systematic process for drawing on external expertise. For example, CDC could create and regularly convene an external advisory panel of academic, government, and industrial partners to provide input and advice on the proposed list of targets relative to agreed-upon selection criteria. Public communication about CDC’s decision making and the independent scientific input to that process is important to help members of the public understand what information is (and is not) being collected about their community and why. In some cases, the decision may be that a pathogen is not yet ready for inclusion because of incomplete understanding of its analytical feasibility in wastewater. In such cases, if the pathogen has current or potential public health significance, CDC should re-evaluate the candidate in the future.

The universe of organisms that can be monitored will evolve over time and with additional knowledge. For example, advances in the application of RNA and DNA sequencing methods and analytical approaches (e.g., metagenomic sequencing) for wastewater samples may also hasten the detection of novel or emerging pathogens. Therefore, a process should be developed to revise the candidate pathogen list as well as the prioritized suite of wastewater surveillance targets regularly, while identifying research and development activities that would help fill important knowledge gaps. This revision process should follow the same practices for inclusion and transparency as the initial selection process. On occasion, global health threats may arise that may necessitate rapid consideration of new wastewater surveillance candidates “off cycle” from the periodic review. This is

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3 See https://www.epa.gov/ccl/basic-information-ccl-and-regulatory-determination.

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

especially likely if the global threat arises from a novel pathogen. In these instances, the advisory panel could be convened on an emergency basis to provide input and comment to CDC on additional proposed wastewater surveillance targets, with in-depth evaluation at the next regularly scheduled review. Thus, the committee envisions a process that is methodical with opportunities for public and expert input while also having the flexibility to move quickly when the need arises.

PUBLIC ACCEPTANCE: LEGAL AND ETHICAL CONSIDERATIONS

The success of a national wastewater surveillance program relies on building public trust in the system (Hrudey et al., 2021). This is a difficult time to be expanding public health surveillance because of the politicization of the COVID-19 pandemic and increase in the proportion of Americans expressing distrust of public health agencies. Such a context can make a seemingly benign public health intervention suspicious to many people.

There is also substantial potential for confusion on the part of the public about the purpose of wastewater surveillance, because “surveillance” is a charged term for some communities. Discussions about expanding wastewater surveillance programs are occurring at a time of pervasive and increasing surveillance of the public by both state and nonstate actors, generating heightened public concern about “surveillance creep” (WHO, 2017). Furthermore, the historical context for these discussions matters, and it bears remembering that one of the earliest proposals for wastewater surveillance was related to monitoring of illegal drug use (Sims et al., 2021). The public’s sense of what wastewater surveillance involves and what its purpose is may be quite different from the community-level infectious-disease monitoring done in the NWSS.

Finally, there may be confusion and difficulty communicating about the kinds of data that are and are not captured in wastewater—especially human DNA—and the potential for identifying specific individuals and households. All of these considerations elevate the need for both careful analysis and skilled communication of ethical issues. Presently, an incomplete understanding of the legal and ethical implications of wastewater surveillance may be impeding some communities from pursuing it, to the detriment of their residents (McClary-Gutierrez et al., 2021).

In this section, the committee reviews legal and ethical considerations and steps that could be taken to address them. Consistent with the study’s focus, this section addresses community-level wastewater surveillance of infectious disease. Collection and analysis at a smaller scale, or use of the data for other purposes (e.g., law enforcement), raises additional concerns but is outside the scope of this analysis.

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

Legal Issues in Community-Level Wastewater Surveillance

Overall, legal concerns raised by community-level wastewater surveillance are minimal. When done purely for public health surveillance purposes, this data collection and analysis does not constitute human subjects research and thus does not implicate federal and state regulations relating to the design and institutional review board review of such research. Another potential legal issue is whether data may be used by law enforcement officials to identify persons who may be violating the law. However, such use is quite improbable because community-level wastewater surveillance examines samples containing information from thousands of households and buildings. There are more cost-effective ways for law enforcers to build a case against those who violate the law (Hall et al., 2012).

Although some legal scholars have discussed the possibility that courts might consider wastewater surveillance an unconstitutional search or seizure (Gable et al., 2020), such a holding is unlikely. The Fourth Amendment to the U.S. Constitution protects individuals against warrantless searches conducted without their permission but only where the individual has a “reasonable expectation of privacy” in the thing or premises being searched. Courts recognize that people do have a reasonable expectation of privacy in their bodily waste in some situations (e.g., a urine sample that is subjected to a drug test), but several lower courts have held that that reasonable expectation terminates when the waste irretrievably flows into a public sewer.4 Courts analogize sewage to garbage: once left out on the curb, one has no right to expect it will remain private.5 Notably, the prior cases on wastewater all involved sampling in a location that would enable the analyst to trace contaminants back to a specific source (e.g., a pipe running from a factory to a public sewer). Because community-level wastewater surveillance involves far lower prospects of identifying particular contributors, the courts’ reasoning applies even more strongly to that context. Some scholars have argued that if individual identification through wastewater surveillance becomes possible, a recent decision by the U.S. Supreme Court holding that people can have a reasonable expectation of privacy in their cell phone location data could change courts’ analyses of wastewater (Ram et al., 2022). But identifying individuals from community-level wastewater monitoring is not technically feasible at this time.

Even if courts did recognize a privacy interest in wastewater, they would still be unlikely to find that wastewater surveillance for infectious disease violates the Fourth Amendment. Provided that the wastewater data

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4 Riverdale Mills Corp. v. Pimpare, 392 F.3d 55 (1st Cir. 2004); United States v. Spain, 515 F.Supp.2d 860 (N.D. Ill. 2007); United States v. Hajduk, 396 F.Supp.2d 1216 (D. Colo. 2005); People v. Elec. Plating Co., 683 N.E.2d 465 (Ill. App. Ct. 1997).

5 California v. Greenwood, 486 U.S. 35 (1988).

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

are used only for public health surveillance and not law enforcement, courts would probably hold that the search is legal under the “special needs” doctrine. This doctrine holds that a warrantless, unconsented search can be constitutionally permissible if it is reasonable and there exists a “special need” for the information apart from law enforcement, such as communicable disease control (Gable et al., 2020; Joh, 2021). For these reasons, there is little basis for concern that community-level wastewater surveillance programs pose constitutional problems.

Ethical Concerns Arising from Community-Level Wastewater Surveillance

Although legal concerns are minimal, two ethical issues arising from community-level wastewater surveillance merit close analysis: ensuring privacy and appropriate use of data.

Privacy

Considering whether wastewater surveillance unduly intrudes on people’s privacy is ethically important because the ordinary moral and legal presumption in the United States is that individuals are entitled to control access to information about their health (Gable et al., 2020). Wastewater contains information about many aspects of the health status of a group of individuals, from diseases to substance use to genetic information. When it is possible to link health information to a particular person or household, the concepts of privacy and “dignitary harm” become salient, particularly if the person or persons did not give permission for their health information to be accessed. There may also be risks—social, reputational, economic, or even physical—to individuals or communities that arise from private health information being accessed. For obvious reasons, it is impossible to obtain individuals’ informed consent to access their information in a community-level wastewater sample, or to allow individuals to opt out of the sample. It is ethically acceptable to conduct public health surveillance under these circumstances (WHO, 2017), but due attention must be paid to minimizing risks and burdens and assuring population benefit (Klingler et al., 2017).

The extent to which wastewater surveillance raises privacy concerns depends on the likelihood that the health information in wastewater can be individually identified. This, in turn, depends on (among other things) the number of individuals represented in a wastewater sample. The smaller the number, the greater the risk of reidentification. At the present time, when wastewater surveillance is done at the community level (Scassa et al., 2022), the risk of identifying individuals or households that made particular contributions to a sample is ordinarily very low. A typical sewershed contains tens of thousands of households or more, and the personal informa-

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

tion collected is both anonymous and aggregated. Therefore, wastewater surveillance can presently be conducted for most communities without troubling implications for privacy.

Sampling on a smaller scale, potentially such as in some sentinel sites or very small sewersheds, involves higher potential risk that particular persons, households, or farms might be identified (CWN, 2020; Gable et al., 2020; Ram et al., 2022), thus meriting additional consideration of ethical and confidentiality concerns and additional data use controls (see below). Sentinel sites themselves should be engaged early in the planning process to ensure that ethical and confidentiality concerns, and other site- or event-specific challenges, are addressed prior to surveillance activities.

Although the degree of privacy intrusion is currently low, public health authorities conducting community-level wastewater surveillance have an ethical obligation to monitor the extent to which the capacity to identify individuals and households from otherwise anonymous data sets (“reidentification”) strengthens over time. It is reasonable to assume that at some point in the future, human reference databases will become robust enough to be able to identify particular genes that are more frequent for particular demographic groups, as well as genes that characterize particular individuals. For these reasons, assessment of the risk of identification should be dynamic rather than a “one-and-done” evaluation. Although it may be tempting to adopt simple heuristics (e.g., the notion that individuals cannot be identified if the sample captures wastewater from 10,000 people or more [Sims et al., 2021]), such assumptions require periodic validation.

In addition to advances in reidentification capabilities, several other future developments would merit reconsideration of current assumptions about privacy-related risks. These include (1) a court ruling that wastewater data can be subpoenaed or are admissible in criminal or civil proceedings unrelated to public health interventions—for example, drug-related prosecutions; (2) any report of wastewater data sharing with law enforcement agencies, or use of wastewater surveillance infrastructure by law enforcement; (3) any shifts in the scale of wastewater data collection or analysis from the community level to more targeted surveillance, such as individual farms or particular neighborhoods (Scassa et al., 2022); and (4) changes in the degree of stigmatization or other adverse consequences likely to flow from a finding of high levels of a pathogen in a particular community.

Appropriate Use of Data

Because analysis of community-level wastewater data for disease surveillance raises few serious ethical concerns but other forms and uses of wastewater data are more problematic, ensuring that data are not mis-

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

appropriated is perhaps the paramount ethical imperative for public health officials. This obligation encompasses several dimensions.

At a basic level, data should be securely stored, with reasonable protections against unauthorized access (hacking). The need for appropriate data security protections is especially great where data from many jurisdictions are consolidated in one platform, creating a single target for hacking or exploitation. Guidance from the Canadian Coalition on Wastewater-related COVID-19 Research goes so far as to recommend giving wastewater data “the same level of security that groups of individual health information data” are given (CWN, 2020, p. 2). However, it is dubious whether such a high level of security is ethically required for community wastewater surveillance data, which are not individually identifiable. Moreover, requiring a high-level information security architecture introduces barriers to the adoption of wastewater surveillance systems. It also has costs in terms of obstructing the flow of data across users for scientifically useful purposes. For these reasons, data security measures need not rival those for more sensitive health data. Nevertheless, it is important to have reasonable systems in place for preventing unauthorized access.

A second dimension of the obligation to ensure appropriate use of data is preventing “function creep,” or expansion of the purposes for which wastewater data are used. To maintain public trust in the wastewater-based infectious disease surveillance system, firewalls must be maintained that prevent transmission of data to aid in law enforcement efforts (Joh, 2021; Ram et al., 2022; Scassa et al., 2022). Infrastructure built for public health surveillance of wastewater (e.g., analytical platforms, periodic water sampling) should not be used by law enforcement officials for their own purposes. Decisions also need to be made about uses of the data by public health officials for purposes other than communicable disease control—for example, estimating substance use in various populations for purposes of allocating programmatic resources (Scassa et al., 2022).

A third dimension of appropriate data use is making wise decisions about data sharing. Prior ethical guidance for wastewater surveillance emphasizes the obligation to share data with other public health agencies (CWN, 2020; Hrudey et al., 2021), and the data sharing obligation arguably extends to academic researchers and others who can assist with analyses, especially during emergencies (Hrudey et al., 2021; WHO, 2017). There is also a strong ethical argument that it extends further, to require sharing of aggregated data with the public (Ram et al., 2022). Members of the public may find such data reports valuable in their efforts to protect themselves—for example, information about SARS-CoV-2 in wastewater in communities with low testing rates allows residents and travelers to take extra precautions (see Chapter 2)—and sharing information learned from wastewater surveillance can help make the benefits of the system clear

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

to the public. Principles of equity and transparency also support sharing findings from wastewater surveillance with key government leaders and the public, accompanied by comprehensible information to help people understand the limitations of the data and the kinds of inferences they can and cannot reliably support.

Whether to share more granular and comprehensive data or actual wastewater samples is a more difficult question. Such data sharing could yield important scientific and public health benefits. On the other hand, the larger the number of users, the greater the risk that misuse of data (e.g., function creep, attempts to identify individuals) will occur, or that data may be analyzed in ways that result in stigmatization of particular communities (Manning and Walton, 2021). Because of these risks, the NWSS does not publicly share even aggregated findings from sewersheds with fewer than 3,000 people;6 access to more granular data is restricted to public health departments (Naughton et al., 2021). Some liberalization of this policy may be warranted, but requests for sharing of samples and more granular data (beyond what is publicly shared) require careful, case-by-case consideration by an appropriately constituted group of experts (e.g., a data use committee). Particular care should be exercised before deciding to share data or samples from surveillance activities at the sub-community level (e.g., sentinel sites). In small-scale cases, the privacy concerns may well outweigh the benefits of data sharing and an access policy like the NWSS’s may be desirable.

Fostering public acceptance necessitates that concerns about data sharing and potential expansions of the scope of wastewater surveillance are addressed and requires good governance, accountability, and transparency (WHO, 2017). These objectives are best pursued through the creation of a decision-making body with public health expertise as well as community representation and statistical and ethics expertise. Such a body is best able to balance the public health mission against countervailing concerns and identify means of minimizing risks that are of concern to the community. For example, statisticians can evaluate the prospects for techniques to minimize risk of identification and the potential effects of proposed linkages to other data sets (Jacobs et al., 2021). Although careful ethical analysis and communication is unlikely to surmount all public concerns, building confidence that an intervention is evidence-based and that officials have heard and considered public concerns about the intervention is essential to the work of building trust and legitimacy (CWN, 2020).

Data use committees (DUCs) have been discussed in the bioethics literature for other situations where secondary uses of data are contemplated and have been adopted in some settings (Scassa et al., 2022). These multi-

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6 See https://nwbe.org/?page_id=77#guidelines.

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

disciplinary committees evaluate proposed secondary uses of data, assessing ethical concerns and the potential scientific benefits. DUCs provide a useful model for ethical governance of wastewater surveillance systems as well. The history of research ethics suggests that only when oversight structures are in place will ethical norms become an ingrained part of practice (Fairchild and Bayer, 2004). Among the tasks that an ethics committee for wastewater surveillance (modeled after DUCs) could undertake is the development of a carefully crafted, standard data use agreement for academic and industry partners who wish to analyze wastewater data. By specifying ground rules for data users, such agreements can minimize the risk that data sharing will result in reidentification or unauthorized analyses.

The ethics committee’s assessment of potential expansions of wastewater data collection or use should anchor on the principles of proportionality, equity, and transparency. Proportionality requires that the public health benefits of an intervention outweigh the burdens and risks—a basic principle of public health ethics. For surveillance efforts, assessing the benefit–risk balance requires ascertaining that the information collected is both useful and actually used and that the burdens on individuals and communities (e.g., stigmatization potential) have been minimized (Lee et al., 2012; WHO, 2017). Minimizing burdens means considering not only whether wastewater surveillance can be performed in a way that reduces risks to individuals and communities but also evaluating whether these burdens and risks are less than other effective methods of disease surveillance. The principle of equity imposes the further requirements that burdens are distributed fairly across communities and that the benefits of wastewater surveillance accrue to the groups whose interests (e.g., privacy) are burdened (Scassa et al., 2022). Finally, the principle of transparency should prompt ethics committees to consider how to explain their recommendations to the public. If the rationale for an expansion in wastewater surveillance cannot be comfortably communicated to the public, that may be a sign that its ethical defensibility is questionable.

ASSURING DATA QUALITY AND ACTIONABILITY

Another important consideration to achieve the vision for a national wastewater surveillance system involves data quality and actionability. State and local wastewater surveillance programs continue to evolve to better serve both local and national needs, and these programs may look different from one locality to the next. But across all systems, reliable data and scientifically sound interpretation are essential so that they are trusted by public health practitioners and the general public.

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

Advancing Data Quality and Comparability

Wastewater surveillance has, by necessity, progressed more rapidly than most other public health surveillance tools; therefore, ongoing efforts are needed to advance data quality and comparability. The COVID-19 pandemic spurred many research laboratories to develop their own analytical methods for wastewater surveillance, including optimizing sample collection and handling, viral concentration, nucleic acid extraction, virus or variant quantification, and computational methods for data analysis. These efforts produced a rich set of resources, but as wastewater surveillance shifts into longer-term and expanded uses, particularly at a national scale, the strengths and weaknesses of different methods need to be assessed and trade-offs rigorously evaluated. Using different methods is reasonable for looking at trends within individual communities, but when implementing a national system, one or a few validated approaches would be best to assure that the data are directly comparable. The vast number of published data sets collected with a diversity of methods will serve as a valuable resource to identify a limited set of the best available methods (e.g., those that best ameliorate wastewater matrix biases and balance quantitative DNA recovery with DNA quality for sequencing).

Even if agreement could be reached about the best available methods, a single standard method may be difficult to implement across a national wastewater surveillance system. Each locality has different technical capabilities and regulatory environments, and localities may have different preferences for use of public health laboratories versus contracted private laboratories. Some methods may be cost-prohibitive for some laboratories (e.g., magnetic bead viral concentration approaches that dramatically increase sensitivity and throughput).

The goal is a national system within which data are comparable across geographic areas for both point estimates of pathogen load and to assess spatial and temporal trends. Some level of methodological flexibility within the national wastewater surveillance system can be afforded as long as expectations for cross-validation with specific samples or standards are established and the data can be transformed by statistical methods into a comparable national-scale data set. Ongoing quality assurance and quality control will be important to provide the data required to correct for specific technical biases introduced by particular methods. Additional effort is needed to compile this information and develop a limited subset of approved methods whose outputs can be statistically transformed into comparable data. The committee’s Phase 2 report will discuss methods for sampling and analysis and quality criteria in more detail.

Several challenges stand in the way of achieving standardized wastewater surveillance data that are comparable across geographic areas, beyond

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

differences in analytical methods. Variability in the data across different localities is introduced through factors such as wastewater system characteristics, population mobility, sampling method, sample transit time, and differences in flow normalization methods to account for dilution due to rainfall or other factors (see also Chapter 3) (Stadler et al., 2020; Wade et al., 2022). All of these issues necessitate ongoing research into best practices to continually improve data standardization methods and resources for disseminating these practices in support of a national wastewater surveillance system.

In summary, a national wastewater surveillance system can accommodate some degree of diversity in sampling and analytical approaches but only if additional investments are made in developing methods for standardizing data for purposes of comparison across geographic areas.

Advancing Data Interpretation and Actionability

In addition to generating reliable and comparable data, a national wastewater surveillance system needs to support timely interpretation of those data to support public health actions. Collecting, analyzing, and statistically interpreting wastewater data on a short turnaround is necessary for the data to be useful. Specifically, “data need to be available within 5–7 days of sample collection to ensure timely application for response decisions” (Kirby et al., 2021). To achieve this, the committee envisions a national data management system that supports rapid data importation from analytical laboratories, quick access to analytical results, easy-to-use data analysis tools appropriate to support the needs of public health decision makers, and public health agency staff who are trained to use the tools and understand the results. Training and capacity building are discussed in more detail in the next section.

Various methods are employed to draw inferences that wastewater data indicate a worsening trend in pathogen load, from tests of statistical significance to application of expert judgment. These analyses require skills that are not always readily available within the jurisdiction or local public health department (McClary-Gutierrez et al., 2021). The NWSS data repository (Data Collation and Integration for Public Health Event Response [DCIPHER]) provides basic analytical tools for states or localities that do not have independent data analytics capacity, although there is room to strengthen and expand available data analysis methods and tools and better integrate with other relevant disease surveillance data. Many localities are developing advances in data analytics, and CDC should learn from these efforts to identify improved approaches to add to DCIPHER and bring these tools to all participating localities. For example, the State of Wisconsin is working with data science researchers to develop benchmarks to better describe an upward trend. Statistical consultants have worked

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

with North Carolina to better discern signal from noise in SARS-CoV-2 trends (Keshaviah et al., 2022a).

Additional research is needed to improve the usefulness and comparability of wastewater surveillance data. Although trend analysis from wastewater surveillance remains a critical interpretation metric for public health monitoring, absolute quantification of the number of infected individuals is not yet firmly established from wastewater surveillance because there have been minimal fecal shedding or epidemiology studies that can help link quantitative SARS-CoV-2 levels to the number of infected individuals. Far fewer data are available for other potential target pathogens for future expanded wastewater surveillance, thus necessitating research and validation studies to establish the basis for interpreting concentration levels of new target pathogens.

In summary, additional investments to accelerate access to wastewater surveillance data and to continue to improve available data analysis methods and robust tools in the NWSS would improve interpretation and enhance the actionability of wastewater surveillance.

BUILDING BROAD AND SUSTAINABLE CAPACITY

Ensuring that wastewater surveillance data are useful for informing public health action requires not only appropriate methods and tools to generate reliable data and information but also sufficient capacity among the partners that make up the wastewater surveillance system and a reasonable expectation that this capacity can be sustained. This includes having a sufficient number of staff for sampling, analysis, and data interpretation; appropriate equipment to perform the work efficiently and effectively; and funding to sustain the program over time. Specialized training will also be important for laboratory and epidemiology practitioners to become familiar with the approach. Wastewater infectious disease surveillance is a relatively new public health strategy in the United States, necessitating continued capacity development and efforts to increase awareness of its benefits.

Creating and Maintaining Operational Capacity for Sampling and Analysis

As the NWSS continues, potentially expanding in geographic and pathogen coverage and settling into long-term processes, attention is needed to ensure that the operational capacity within laboratories and wastewater utilities—both staffing and equipment—is appropriately developed and maintained to support the system moving forward.

Participation of wastewater utilities is the backbone of the surveillance system. Although utilities routinely collect inflow samples as part of opera-

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

tional or compliance sampling to ensure proper performance, wastewater surveillance involves stricter sampling requirements and additional efforts to ship the samples to an analytical laboratory. Many utilities began sampling programs as an in-kind service in response to a national crisis. As surveillance becomes routine, the burden of sampling and personnel time needs to be compensated through funding mechanisms. Streamlined mechanisms to provide ongoing funding support for staff, equipment, and other expenses should continue to be pursued to support sustainable capacity. Utilities can contribute valuable insights about system characteristics, such as flow and industrial inputs, to support better data analysis and interpretation, and involving wastewater utilities in the design and refinement of surveillance sampling is also important to gain long-term buy-in. Strong relationships between public health agencies and wastewater utilities will help ensure that these partners remain engaged and prepared if increased surveillance activities are triggered. CDC, EPA, and stakeholder groups such as the Water Environment Federation (WEF) can help support and facilitate these relationships. WEF is also facilitating training and sharing of expertise among utilities through one of the Communities of Practice (see Box 4-1).

Analytical laboratories are another critical partner in wastewater surveillance. Initial development and monitoring for SARS-CoV-2 occurred in research laboratories in many localities, but wastewater surveillance sample analysis is now transitioning to public health laboratories or private laboratories. Essentials for this transition include space, instrumentation, and personnel with specialized wastewater analysis training. Wastewater samples are unlike clinical samples, have a high level of heterogeneity, and often require troubleshooting, even after methods are established. Specific training and experience with sample handling, analysis, and data interpretation are needed. CDC has established a national commercial testing contract to support those without public health laboratory capacity.

Maintaining some level of baseline wastewater infectious disease surveillance, even at a low level, is important to ensure that the institutional framework will be in place to broaden and/or scale up efforts, as needed, in the face of new or re-emerging threats. Ongoing training and succession planning will be important to maintain the expertise.

Increased investment in technology development that covers sampling devices and analytical methods would also strengthen the capacity of a national wastewater surveillance system. The current state of the art in wastewater surveillance has been advanced rapidly by new technologies during the COVID-19 pandemic, but further technological advances can help scale up and generalize deployment. For example, advances in nucleic acid sequencing could reduce cost and turnaround time. Flow-weighted sampling equipment is expensive, fragile, and prone to clogging. As new

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

methods continue to emerge, CDC will need to support the development of standards, including reference materials, and approaches for cross-laboratory validation of analytical methods.

Improving Capacity for Local Interpretation of Wastewater Surveillance Data

A robust wastewater surveillance system requires strong capacity for analyzing and interpreting data in support of decision making at the state,

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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tribal, local, and territorial levels. Currently, local interpretation and use of wastewater surveillance data range widely, and a number of communities collect the samples but do not use the data for local decision making, largely due to limitations in workforce capacity and training. Guidance and training on the analysis and interpretation of wastewater data would help build understanding and confidence in evaluating wastewater data patterns and using that information for public health decisions.

Looking forward toward an expanded NWSS, public health guidance and training will need to include the following:

  • How to interpret the implications of wastewater surveillance data for disease epidemiology across a range of pathogens. For example, what does a positive sample for a given infectious disease imply about the likelihood of a case of a disease in the catchment population? What does an increasing trend, concentration of a given level, or other wastewater information imply about the population patterns of disease?
  • Explanations of the wastewater surveillance data analysis approaches that would be appropriate for different use cases, including their limitations and when they can and cannot be validly applied.
  • Clear, nontechnical guidance on the standards for wastewater surveillance collection and laboratory methods so that public health personnel who may not have laboratory training can understand the potential applications, uses, and limitations of different data sets.
  • Explanation of NWSS analytical capabilities, use case examples, and the basis for interpretations provided from nationally based analytical pipelines.

It is not necessary that all public health personnel be trained on all aspects of wastewater surveillance (i.e., methods, data analysis, interpretation, and potential actions). Rather, an individual or smaller group from state, tribal, local, and territorial health departments could participate in such training and serve as a liaison to enable information sharing and coordination within the NWSS and other units within a public health jurisdiction. Trained state personnel can also serve as a resource and provide guidance to local health departments within the state.

One of the largest initial barriers among public health practitioners to using wastewater surveillance data was unfamiliarity (Keshaviah et al., 2022b; McClary-Gutierrez et al., 2021). Seeing how others use these data in their own community raises confidence (McClary-Gutierrez et al., 2021), and CDC Communities of Practice (see Box 4-1) provide opportunities for laboratory personnel and public health practitioners to make connections among peers and share their experiences and lessons learned. Also,

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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the formation of smaller cohorts has been beneficial to build relationships among individual entities and encourage peer-to-peer discussion. Dedicated sessions at professional conferences, such as the Council of State and Territorial Epidemiologists Annual Conference, would increase exposure to community-based wastewater surveillance, which is becoming a highly interdisciplinary specialty. Additionally, the new COVID-19 National Wastewater Surveillance System Centers of Excellence (see Box 4-2) can further support public health practitioners through training and development of best practices.

In summary, training public health practitioners and improving access to those with experience with wastewater surveillance implementation, analysis, and data interpretation is expected to increase the use of wastewater surveillance data for public health action.

Expanding the Talent Pipeline

Training within university programs in biomedical informatics, bio-statistics, environmental engineering, epidemiology, microbiology, or other related fields is necessary to develop and maintain a workforce with the

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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qualifications needed to continuously improve and execute wastewater surveillance in public health laboratories and departments. For example, laboratories could coordinate with academic programs to provide opportunities for internships to support the talent pipeline of students moving into careers in applied public health. Three workforce gaps that urgently need to be filled are in the areas of epidemiology, health informatics, and bioinformatics.

Within the public health system, one of the major limiting factors for capacity building is recruiting and retaining skilled epidemiologists. Wastewater surveillance requires analyzing novel, high-dimensional data and developing completely new analytic approaches. The skills required go far beyond those of most entry-level epidemiologists. Highly trained, PhD-level epidemiologists are currently in short supply due to the increase in demand during the COVID-19 pandemic. Cross-training to include environmental engineering aspects of wastewater surveillance would be particularly valuable.

Robust health informatics support that can set up and maintain complex systems is needed for automating and disseminating wastewater data efficiently. A wide range of health informatics is involved in wastewater surveillance that, ideally, would be integrated with other data streams within the public health system. Automating data streams and reporting is essential for long-term sustainability and efficiency. Informatics expertise is also needed for creating dashboard interfaces and automating customizable reports to be meaningful to various stakeholders, including wastewater utilities, local health departments, and policy makers.

Bioinformatics expertise for sequence analysis is essential to analyze and interpret complex sequence data. Bioinformatics training needs for wastewater surveillance are distinct from expertise in most clinical sequencing because wastewater contains a composite mixture of different strains and variants of targets of interest rather than the single strain typically found in a given clinical sample.

Predictable and Sustained Funding

Wastewater surveillance is in its infancy as a field, and to date, CDC funding has been critical to the advancement of the field and establishment of the NWSS. To maintain and advance wastewater surveillance and retain participation of states, tribes, territories, and localities in the NWSS, it is critical that sustained, predictable federal funding remain available. Predictable and sustained CDC funding is needed in two key areas:

  1. to support capacity building (e.g., trained staff, appropriate equipment) as the system transitions from emergency pandemic response to a sustained program; and
Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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  1. advances in science and technology so that the NWSS can continue to improve its capability and address additional organisms, including emerging pathogens, for which limited information may be available (see Figure 4-1).

For example, technology advancements and process improvements could include new methods for sample concentration and new algorithms for analyzing data. Long-term research investments are also needed to adapt methods for evolving SARS-CoV-2 variants, develop and validate new targets, and realize the full potential of wastewater surveillance. These technology development and science needs span topics traditionally funded by different government agencies (e.g., National Institutes of Health [NIH], National Science Foundation [NSF], National Institute of Standards and Technology [NIST], EPA, U.S. Food and Drug Administration, U.S. Department of Agriculture (USDA), and National Oceanic and Atmospheric Administration), private sources (e.g., Rockefeller Foundation, Alfred P. Sloan Foundation), and companies. Unpredictable funding makes it highly challenging to retain laboratory personnel, informaticians, and public health epidemiologists who are vital to maintaining a surveillance system and to recruit students, researchers, and companies to participate in these efforts.

ACHIEVING INTEGRATION AND COLLABORATION

Achieving the vision of an integrated, actionable wastewater surveillance program requires coordination and collaboration across many par-

Image
FIGURE 4-1 Areas for sustained investment to support the National Wastewater Surveillance System (NWSS).
Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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ties within the public health system, including local public health agencies, CDC, analytical laboratories, and wastewater utilities. A coordination strategy will be unique to the individual state, tribe, locality, or territory, but clear designation of roles (e.g., sample collection, laboratory analysis, data interpretation and integration, and data dissemination) will be necessary. Typically, the primary public health agency7 overseeing the wastewater surveillance program provides data interpretations and ensures that the wastewater data are integrated with other data sources (e.g., clinical testing, syndromic data) to inform sound decision making. This effort requires not only coordination with laboratories whose staff understand methodological constraints and utilities that provide analytical context and important expertise for working with the complex matrix of wastewater but also coordination within public health jurisdictions, including epidemiologists and practitioners who ultimately use the data to decide upon public health actions. Furthermore, to build out the system, innovation and progressive improvement of analytical methods, sampling approaches, and data analysis tools and methods are needed, which often fall upon academics and other entities within the scientific community that have expertise in moving analytical techniques and data analysis approaches from discovery to implementation.

Coordination Within Public Health Jurisdictions

Early adopters of wastewater surveillance have developed helpful models for coordination within public health jurisdictions to better support decision making, although the optimal approach may vary across localities. Some jurisdictions are small and lack capacity to undertake new activities, deferring to state public health systems to implement wastewater surveillance, while large municipalities or counties may operate their own surveillance systems. Typically, a primary lead wastewater surveillance group is established within a larger public health agency to compile and interpret data and actively engage partners (see Figure 4-2). Practitioners within these units are often familiar with the complexities of environmental samples and with epidemiology and community health interventions. These units often serve as liaisons between the analytical laboratory and other components of a public health agency or system (e.g., infectious diseases, epidemiology). This lead group can help bridge communication gaps between highly technical environmental engineering or laboratory information and epidemiological considerations and public health actions

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7 For the purposes of this report, primary is considered to be one of the 64 state, territorial, city, or county health departments eligible for Epidemiology and Laboratory Capacity (ELC) funding (see also Chapter 1).

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×
Image
FIGURE 4-2 Framework for wastewater surveillance coordination and collaboration within the public health system. The public health agency’s wastewater surveillance group collaborates with wastewater utilities and laboratories, which play a critical role in providing samples, data, and expertise, and also leads internal coordination with infectious disease/epidemiology teams to integrate wastewater data into public health actions. The public health agency typically represents the primary organization receiving ELC funding (e.g., states, large cities/counties) but may also include other large cities and counties with sufficient staff capacity for data analysis and coordination. State public health agencies typically also coordinate with local public health departments, which serve as the frontline of public health response, The scientific community is critical for advancing wastewater surveillance for new technologies, research, and training.

in infectious disease. Technical expertise needed within a core, lead wastewater surveillance group includes epidemiology, environmental engineering, and sound technical knowledge for laboratory analysis. Certain aspects of the expertise could be gained from engaging team members from outside of the unit, such as from wastewater utilities or the analytical laboratory.

It is critical that the environmental and communicable disease arms of the public health system have close coordination with wastewater surveillance teams. For example, an organization may include the same epidemiologists who are involved in wastewater surveillance in the agency’s overall epidemiology response teams. Public health practitioners, who are ultimately the end users of the data, have the contextual knowledge to drive the data needs to identify how wastewater data can best inform

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

interventions. There should be two-way communication between the different units, including crafting public-facing messaging with the communications teams.

To maximize actionability, local health departments need to be engaged, because they can provide input on community characteristics and ensure local buy-in. State public health systems that lead wastewater surveillance efforts are excellent points of contact for local and county public health officials and will be most familiar with the state’s specific needs, barriers, and vulnerable populations. Many large municipalities (e.g., Chicago, Houston, and Santa Clara County) already have robust public health systems and operate sophisticated wastewater surveillance teams that cover large populations.

Collaboration with Analytical Laboratories

Many states and localities are implementing wastewater surveillance successfully in their own public health laboratories, which are centralized and have the necessary equipment. The response to the COVID-19 pandemic spurred improvements in analytical capacity, and training and retention of key personnel is needed to create institutional knowledge. This laboratory expertise should be integrated into public health wastewater surveillance teams. However, some states, tribes, localities, and territories may choose to use academic, commercial, or utilities-based laboratories rather than building laboratory capacity within the public health system. Regardless of whether the laboratory capacity is within the public health agency or external, coordination is essential to understand issues with data comparability due to methodological differences, instrumentation, or other factors. Close communication, such as biweekly calls that include representatives of the public health agency wastewater surveillance group and analytical laboratory, allow for relatively early reactions to data anomalies, and ongoing interactions provide opportunities to understand methodological influences on data trends over longer periods of time. Good communication between the laboratory and the wastewater facilities is also important to obtain necessary parameters for samples and understand the system and representativeness of the samples.

Collaboration with Wastewater Utilities

Wastewater utilities have knowledge critical to interpreting data that includes sample representativeness, sewershed boundaries, and sample interferences and complications due to operational procedures; therefore, they need to be engaged as full partners. Because the samples themselves are not uniform, wastewater expertise is especially needed to understand

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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uncertainty and variability in the data. Coordination with utilities for sampling often occurs on the local level because local public health entities and wastewater utilities may already interact; however, when such relationships are lacking, state- or national-level assistance with coordination may be needed. National utility member associations, like the WEF, have utility Communities of Practice that can forge and maintain public health/utility partnerships, and facilitate communication among other Communities of Practice and health agencies. Wastewater utilities ideally should interact with both the laboratory and the wastewater surveillance group within the public health agency because their expertise would be important to accurate interpretation of the data. The lead public health wastewater group should proactively invite wastewater utilities to participate beyond providing samples at the level that they are able given personnel and other capacity constraints.

Additionally, some large utilities have research groups or extensive laboratory expertise that would be highly beneficial to draw upon for operating a wastewater surveillance program. For example, Los Angeles Sanitation District and Hampton Roads Sanitation District began wastewater programs early in the COVID-19 pandemic and were able to provide guidance to others in the field.

Coordination and Collaboration with CDC and Other Federal Partners

Federal-level coordination through CDC to harness the strengths of other federal partners is essential to streamline data curation and visualization, coordinate new method implementation, facilitate training for public health practitioners, conduct public outreach, and provide predictable and sustainable funding. As the surveillance system expands beyond SARS-CoV-2, CDC—the nation’s health protection agency—is the logical entity to coordinate the process for the selection of new agents, including working with outside experts who can advise on targets, sampling schemes, data presentation, and interpretation. For emerging diseases and pathogens with zoonotic potential, close coordination with animal health agencies and laboratories (e.g., USDA and the National Animal Health Laboratory Network), is essential to ensure informed and coordinated investigations and response activities.

One major function of CDC’s NWSS program will be to coordinate and maintain the data repository and support analytical and visualization tools that are available to national, state, tribal, local, and territorial public health agencies as well as the publicly accessible dashboard. A uniform yet flexible data framework will enable comparisons within and across states, while capturing as many reliable data sources as possible. Data analysis tools provided within this framework (with supporting guidance) will make

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
×

public health actions more accessible for states, tribes, localities, and territories that do not necessarily have the internal expertise to contextualize wastewater data within other public health surveillance efforts.

CDC currently supports and coordinates Communities of Practice (see Box 4-1), which provide valuable information sharing within individual communities for laboratories, public health practitioners, and wastewater utilities. These communities will be important to achieve the vision of a national wastewater surveillance system as it expands to new areas and new pathogens. CDC can strengthen these efforts by coordinating proficiency and round-robin testing (i.e., exchanging samples for comparisons), and engaging academic or industry expertise as needed to interact with the localities performing surveillance. CDC is currently funding two Centers of Excellence (see Box 4-2) that can provide training in both data generation and data interpretation, develop model communications such as reporting formats and outreach materials, provide rapid devolvement and validation of new targets, and backfill critical knowledge gaps in methods and surveillance approaches.

Another important role for federal agencies is to identify and support high-priority research needs associated with national wastewater surveillance. Such investments solidify the knowledge base on which wastewater surveillance is built and promote ongoing advancements in the field that ultimately will enable more informed public health actions. For example, research is needed to fill knowledge gaps regarding the dynamics of SARS-CoV-2 from infected individuals through wastewater systems as well as to understand the epidemiological links between the numbers of infected persons and wastewater measurements. CDC should coordinate with other relevant federal agencies (e.g., NSF, NIH, EPA, and U.S. Geological Survey) to identify and fund high-priority research. Coordination with NIST for creating resources of readily available standards will be important to support comparability across the national system and assurance of good data.

Finally, perhaps the most critical function of the federal government is to provide predictable and sustained funding that supports equitable coverage across a national system.

Collaboration with the Broader Scientific Community

Early in the COVID-19 pandemic, university laboratories and water or wastewater utilities drove much of the innovation and rapid implementation of SARS-CoV-2 surveillance and, in doing so, established critically important partnerships (Hoar et al., In Press). Research laboratories are now transitioning away from bulk processing and analysis of samples that now can be analyzed through public health or private analytical laboratories. Looking forward, research laboratories, located in a diversity

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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of health, engineering, and environmental science units both within and outside of academia, can provide an avenue for rapid method development for new pathogen targets, improvement of assays for low-level targets in wastewater, and advancement of modeling and data analysis for current and emerging microbial threats. Existing and new partnerships among the scientific community; analytical laboratories; wastewater utilities; and local, state, tribal, territorial, and national public health agencies provide mechanisms for identifying challenges that could be addressed through research and innovation as well as rapid translation of scientific advances into operations.

The formal designation of two Centers of Excellence (see Box 4-1), the Houston NWSS and the Colorado Department of Public Health and Environment/University of Denver, reflects the importance CDC is placing on external partners within the scientific community. These Centers of Excellence are expected to strengthen connections between the NWSS and the experts in the scientific community, but they cannot cover all the research needs of the NWSS. To support useful expansion of the NWSS beyond SARS-CoV-2, basic discovery and developmental research will be needed to address gaps in understanding. This research includes assessments of whether potential pathogens of concern are detectable and stable in wastewater, and development of sample preservation and analysis methods. In the longer term (5–10 years), new cost-effective methods need to be developed for untargeted pathogen biomarker detection to ensure rapid response to emerging pathogens. Additionally, rapid approaches for adapting target-specific methods to new pathogens would strengthen the response capacity to emerging microbial threats. This will require research into the fundamental chemistry, physics, and microfabrication of novel sequencing systems, likely as a mixture of research at academic institutions, national laboratories, and companies, casting a broad net for new high-risk, high-reward approaches. Phase 2 of the committee’s study will examine research needs in detail. CDC should support targeted research and innovation through funding mechanisms such as the CDC Broad Agency Announcements.

In addition to its role in scientific discovery and development, academia will have a key role in workforce training (Hoar et al., 2022). These workforce needs will include the full spectrum of wastewater surveillance from sampling methods and design to laboratory analysis, data analysis, data interpretation, and communication. Understanding the current and future workforce needs will be a critical element in planning. A workforce assessment for the NWSS could identify specific training needs that can be met by community colleges as well as by research universities.

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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CONCLUSIONS AND RECOMMENDATIONS

CDC should develop an open and transparent process for prioritizing targets for wastewater surveillance. Selecting future targets for wastewater surveillance is a challenging endeavor that balances potential health benefits against resource investments and the capabilities of existing technology. CDC would benefit from an independent external advisory panel, with representation from industry, academia, and public health, to provide periodic guidance and input to this process and ensure that the latest advancements in science and technology are considered. The external advisory panel could also provide rapid consultation in future pandemic emergencies. Public input to the process is important because the community should have the opportunity to have concerns heard and considered before a final plan is implemented.

Although the committee judges that the benefits of responsibly managed wastewater surveillance outweigh the associated ethical concerns, CDC should address privacy concerns through clear public communication and by convening an ethics advisory committee. CDC should develop and disseminate additional public communications designed to inform the public about the data generated in wastewater surveillance and how these data are used. In addition, CDC should empanel a standing ethics advisory committee to recommend guidelines about the conditions under which wastewater data may be shared with others and to evaluate future expansions of data collection and data access. It is desirable for academic and industry partners to be able to conduct and contribute analyses of wastewater data, which requires responsible data sharing. The ethics committee, which could be modeled after existing data use committees, should create a formal process for executing data use agreements to help address privacy concerns and alleviate burdens in managing data sharing at a local level. Furthermore, if the prospects for identifying individuals in wastewater data strengthen over time, or if any agency or private-sector organization expresses interest in using wastewater data for purposes other than infectious disease surveillance, this body should re-evaluate the balance of health benefits versus risks associated with data sharing and any proposed expansions in data collection and data linkage. There should be a strong firewall maintained that precludes use of data by law enforcement. In performing its work, the ethics body should consider whether steps are needed to help avoid stigmatization of particular communities or to build further buy-in to wastewater surveillance among members of particular communities.

The effectiveness of the NWSS will depend on predictable and sustained federal investments. The COVID-19 pandemic emergency spurred many researchers and utilities to volunteer their labor and donate resources

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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in support of the effort, but the vision of a sustained national wastewater surveillance system necessitates a shift from volunteerism to a strategic national plan with well-defined roles supported by federal investments. Federal funding is needed to continue to advance sampling and analysis methods and data analysis tools to improve data quality, comparability, and actionability. Predictable funding is also essential to maintain the workforce capacity and institutional knowledge to sustain a well-functioning wastewater surveillance system that is useful to public health agencies and to support an effective system for data management and interpretation for all public health agencies.

Close coordination among public health agencies, analytical laboratories, and wastewater utilities is essential to generate reliable data and support appropriate data interpretation and use. CDC’s Communities of Practice for wastewater utilities, laboratory personnel, and public health practitioners provide valuable support for coordination within each of these fields, and CDC can work with these communities to establish expectations for coordination and collaboration with other agencies. State, tribal, local, and territorial public health agencies should also work to strengthen relationships across these partners—for example, by encouraging biweekly meetings with staff from the public health agency, the analytical laboratory department, and the wastewater utility, as appropriate, in support of data interpretation. CDC, as the nation’s health protection agency, should continue to lead the coordination of the many federal partners in support of this effort.

Because the function of the NWSS depends on the participation of wastewater utilities, CDC and local public health agencies should continue to strengthen relationships with wastewater partners. CDC should continue to work to improve the connections between wastewater utilities and local, state, tribal, territorial, and federal public health agencies, beyond what is currently provided in the Communities of Practice. At a federal level, CDC could set expectations and standards of practice that utilities be engaged as full partners, with compensation for their participation and education and data sharing to ensure that the utilities see the value of their contributions. Local public health agencies should work to build relationships with utilities, who can also provide important expertise essential to developing sound sampling designs and accurate data interpretation.

Looking forward, academia and the broader scientific community are essential to drive innovation in sampling, laboratory analysis, data management and interpretation, and public communication. CDC is commended for launching two initial Centers of Excellence, which will help support targeted research and training. In addition to the Centers of Excellence, CDC should engage the scientific community around specific sampling, analytical, and data management needs through funding mechanisms such

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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as the CDC Broad Agency Announcements. Academic and other research laboratories could provide needed training, and an NWSS workforce needs study would help ensure that a trained workforce can meet current and future needs.

Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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Suggested Citation:"4 Strategies for Achieving the Vision and Increasing the Public Health Impact of National Wastewater Surveillance." National Academies of Sciences, Engineering, and Medicine. 2023. Wastewater-based Disease Surveillance for Public Health Action. Washington, DC: The National Academies Press. doi: 10.17226/26767.
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The COVID-19 pandemic spurred a rapid expansion of wastewater-based infectious disease surveillance systems to monitor and anticipate disease trends in communities.The Centers for Disease Control and Prevention (CDC) launched the National Wastewater Surveillance System in September 2020 to help coordinate and build upon those efforts. Produced at the request of CDC, this report reviews the usefulness of community-level wastewater surveillance during the pandemic and assesses its potential value for control and prevention of infectious diseases beyond COVID-19.

Wastewater-based Disease Surveillance for Public Health Action concludes that wastewater surveillance is and will continue to be a valuable component of infectious disease management. This report presents a vision for a national wastewater surveillance system that would track multiple pathogens simultaneously and pivot quickly to detect emerging pathogens, and it offers recommendations to ensure that the system is flexible, equitable, and economically sustainable for informing public health actions. The report also recommends approaches to address ethical and privacy concerns and develop a more representative wastewater surveillance system. Predictable and sustained federal funding as well as ongoing coordination and collaboration among many partners will be critical to the effectiveness of efforts moving forward.

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