Is wastewater surveillance really enough?

By Alison Adduono, Director of Marketing Communications

When the Public Health Emergency (PHE) Declaration ended on May 11, 2023, things changed as far as how COVID-19 tracking and reporting was being handled. In the past health officials were required to submit their patient COVID-19 test results to the CDC and with the end of the PHE this mandate went away. Now COVID-19 is being measured with the following metrics:

Emergency room visits
Hospital admissions
The National Vital Statistics System (NVSS) death records
Regional-level test positivity data from the National Respiratory and Enteric Virus Surveillance System (NREVSS)
Wastewater surveillance and genomic surveillance¹

Why is wastewater surveillance being used?

In September 2020, the CDC launched the National Wastewater Surveillance System (NWSS) to monitor SARS-CoV-2 in wastewater and has invested over $100M in its infrastucture.² Since its inception over 1000 testing sites have come on board providing screening data of approximately 130 million people nationwide.

To decode the genetic information of infectious disease pathogens, whole-genome sequencing (WGS) technology is used. Because the virus's RNA breaks into pieces in wastewater, WGS cannot confirm the presence of any specific variant in wastewater, but it can detect variant-defining mutations in wastewater samples, which can be a powerful early indicator that a variant is likely to exist or is spreading in the community before clinical cases are reported.³

COVID-19 Wastewater Analysis Testing
*Photo Credit: iStock by Getty Images*

How does wastewater tracking work?

Individuals infected with COVID-19 (even those that are not displaying symptoms) shed the virus in their fecal matter which finds its way into wastewater after being flushed through the toilet and sewage system. Technicians take samples of this wastewater before it reaches the treatment plant and send it off to laboratories to test and measure for virus levels. This data is then provided to public health officials for reporting and trending. According to the CDC, this data becomes available 5-7 days post flush.⁴ Biobot Analytics is another resource for this information.

What testing methods are used?

United States wastewater is tested for SARS-CoV-2 using a variety of testing methods and laboratory workflows. In order to ensure that the data obtained from testing can be interpreted for Public Health Surveillance purposes, sample processing steps are utilized, laboratory controls are used, and biosafety measures are implemented.⁵

What are the benefits?

Water surveillance can be an early indicator that COVID-19 cases are increasing or decreasing in a community. It can detect even small changes that can be used as a call to action.
It does not depend on people having access to healthcare, people seeking healthcare when sick, or the availability of COVID-19 testing.
Wastewater testing near me --- As nearly 80 percent of US households use municipal wastewater collections, sewage testing and monitoring can be implemented in many communities.⁶

Can wastewater surveillance provide an early warning of other infectious diseases such as Monkeypox?

According to the CDC, in addition to providing an early warning for COVID-19 spread, wastewater monitoring can provide an early warning of Monkeypox (Mpox) activity and provides routine data on its detection.⁷ Since influenza and Polio testing have already been done using this method too, it is possible that it can be used for other infectious diseases. However, there is still work to be done.⁸

What is the downside?

In an interview with The Guardian, Jennifer Nuzzo, an epidemiologist and director of the Pandemic Center at Brown University School of Public Health, cautioned that “We can’t link the wastewater data to people,” and that “It’s totally anonymous.” So, health officials struggle with being able to determine who is infected and spreading the virus from person to person. And while this testing does allow us to see the new variants in a community, she also questioned how early we will see them with this testing.⁹

Since the CDC wastewater surveillance program’s measures are limited to its reliance on public wastewater treatment works, it is difficult to discern the exact magnitude of the virus. Communities or facilities served by decentralized wastewater systems (i.e., prisons, schools, or hospitals that treat their own wastewater), as well as rural, small counties, or areas using individual septic systems, are excluded from the public wastewater system. This means that their data is not captured by this method of surveillance.³

Disease Tracking

In conjunction with wastewater tracking, the CDC maintains a database that is updated weekly that monitors positivity rates, emergency room visits, hospitalizations and deaths rates by US county. They also maintain a tracker specifically for wastewater surveillance.

Recommendation

As we enter the respiratory season, Nuzzo recommends that in addition to wastewater testing we also have proactive targeted COVID testing of individuals in assisted living/nursing homes, low to moderate income communities, and rural areas with inadequate healthcare access.⁹

Resources:

Where Speed, Efficiency, & Accuracy Align

The AscencioDx® Covid-19 Test and The AscencioDx® Molecular Detector have not been FDA cleared or approved, but have been authorized for emergency use by FDA under an EUA for use by authorized laboratories. This product has been authorized only for the detection of nucleic acid from SARS-CoV-2, not for any other viruses or pathogens. The emergency use of this product is only authorized for the duration of the declaration that circumstances exist justifying the authorization of emergency use of in vitro diagnostics for detection and/or diagnosis of COVID-19 under Section 564(b)(1) of the Federal Food, Drug, and Cosmetic Act, 21 U.S.C. § 360bbb-3(b)(1), unless the declaration is terminated or authorization is revoked sooner.

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