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CDC Launches Public COVID-19 Wastewater Surveillance Dashboard

NEW YORK – The US Centers for Disease Control and Prevention has launched an online public dashboard aggregating national data on COVID-19 wastewater surveillance. The PCR-based approach — which gives an early warning signal that can be used to inform public health efforts and resource allocation — will also be adapted to other pathogens in the future, the CDC said.

In a briefing with the media Friday morning, the CDC noted that the new dashboard will now be updated daily and will provide data on SARS-CoV-2 wastewater trends over the previous 15-day period as well as percent positivity testing data from the participating communities. This data was previously available on a state-by-state basis, but the dashboard now enables direct comparisons between sites.

Amy Kirby, the team lead for the CDC's National Wastewater Surveillance System (NWSS), said in the briefing that the agency is currently aggregating data from 400 testing sites in 37 states, four cities, and two US territories.

In addition, the agency expects another 250 sites to go live in the next few weeks, she said.

"We have developed a suite of resources to help our health departments build this capacity," Kirby said. The CDC also has a commercial testing contract with LuminUltra supporting twice-weekly testing at an additional 500 sites nationwide as different communities go live with their systems.

Begun in September 2020, the NWSS program has so far supported testing of more than 34,000 wastewater samples, which represents approximately 53 million Americans, said Kirby.

"We've already seen examples of cities and counties using their wastewater testing to better understand the trajectory of a surge of infections — now more communities will have the opportunity to use this tool to help guide their public health decision making," she said.

SARS-CoV-2 virus is shed in feces at high concentrations early in infection and can therefore give a one- to two-week head start on potential local increases in cases and hospitalizations.

Wastewater is sampled from sewer sheds and represents a pooled sample from a so-called catchment area of local residents. When samples arrive at the lab, virus is concentrated and RT-qPCR and quality control tests are run, then this data is submitted to CDC for analysis, Kirby said.

The data is then reported back to the local area. Now, it will also be shared publicly on the dashboard. Although not every site has data on the dashboard as of today, Kirby said these will be up and running shortly.

Kirby noted that the data can be used in conjunction with other public health information to enhance "situational awareness" of local infections.

Because the method — also called wastewater-based epidemiology — detects both symptomatic and asymptomatic cases, it can also provide unique data. Normally, unless a person is tested, and tested in a way that is reported to public health, their infection would not be logged by typical means. However, it would still show up as a signal in wastewater.

And, "As our testing strategy changes [and] more people use at-home tests instead of reported tests, wastewater surveillance will continue to be a robust approach to understanding what is going on in communities," she said.

Kirby said NWWS will also expand to gather data on other pathogens in wastewater soon. These will include antibiotic resistant bacteria, foodborne pathogens, influenza, and Candida auris. The CDC is also considering the merits of using the platform to surveil for opioids, she said. This could provide a means to better direct public health efforts in what is essentially a parallel, and ongoing, epidemic of increasing substance abuse-related mortality.

"One of the strengths of wastewater surveillance is that it is very flexible," Kirby said. "Once we have built this infrastructure ... we can add tests for new pathogens fairly quickly," she added, noting that the system could be ramped up "within a few weeks" to detect something new.

The recent report of "cryptic" variants was notable, and Kirby said her team is in contact with the researchers who reported the signal, but generally the NWSS program is geared to track known variants rather than discover new ones. However, she also said that some labs in the NWSS program are using sequencing to analyze samples, and the dashboard reports that data as well.

The agency has funding to support all of the sites currently in the program through 2025, and Kirby said it expects to expand the budget this year.

Although some of the WBE efforts in the US were initially spearheaded by academic labs, the CDC expects the ultimate home for this work to be in public health and environmental health labs.

Public health labs are also finding new ways to use the data, Kirby said. "They can use that information to make decisions about resources — where are they going to send mobile testing sites, where do they need to send additional hospital supplies — we have also seen them use this information to look for variants of concern in their communities," she said.

A wastewater signal trending upwards could benefit communities, she also said, so that they might increase masking, distancing, and self-testing for example. "With wastewater testing, you can start doing those a few days earlier, and those extra days can really make a difference in the ultimate trajectory of that surge in your community," Kirby said.