FRIDAY, Feb. 4, 2022 (HealthDay News) — It’s less enchanting than reading tea leaves, but federal health officials announced Friday they are expanding nationwide efforts to track COVID-19 by monitoring levels of viruses found in raw sewage.
The U.S. Centers for Disease Control and Prevention plans to add 250 more monitoring sites over the next few weeks to a list of more than 400 places that already routinely test their sewage for bits of the COVID-19 virus, Amy Kirby, program manager for the CDC’s National Wastewater Surveillance System, said during a morning press conference.
“Because the increase in sewage [virus] typically occur before corresponding increases in clinical cases, wastewater monitoring serves as an early warning system for the emergence of COVID-19 in a community,” Kirby said. “These data are particularly powerful because they capture the presence of infections in people with and without symptoms, and they are not affected by access to healthcare or the availability of clinical tests.”
The CDC also adds wastewater monitoring data on the agency’s COVID Data Tracker site, so people can see trends in their communities, Kirby added.
Estimates suggest that between 40% and 80% of people infected with COVID-19 shed viral RNA in their stool, whether or not they have developed symptoms, Kirby said.
“Shedding in the faeces starts very soon after a person is infected. It’s actually one of the first signs of infection that we see, which is really important for this early warning capability. for sewage,” Kirby said. “We see these levels go up very, very high, so a lot of the virus is shed in the feces very early in the infection and then it stops.”
With this in mind, the CDC launched the National Wastewater Surveillance System (NWSS) in September 2020 to warn communities facing a future outbreak of COVID-19. The NWSS now collects more than 34,000 samples a day representing about 53 million Americans, Kirby said.
Public health agencies can use COVID sewage tracking to plan where to place mobile testing and vaccination sites within communities, as well as alert local hospitals to prepare for an upcoming wave, Kirby noted.
Some states also perform genetic sequencing on their wastewater samples, she added, to track the potential emergence of new COVID variants.
The New York City Wastewater Tracking Program recently detected fragments of COVID-19 with unique mutations never before seen in human patients. These ‘cryptic lineages’ could be evidence of new variants, researchers reported Thursday in the journal Nature Communication.
“Many of our states are sequencing their wastewater samples, and that data will be coming to the CDC in the next few weeks. We’ll have that to watch as well,” Kirby said. “It’s a very powerful method for tracking variants of concern in wastewater.”
Tracking sewage for viruses is not a new concept, Kirby said. Overseas localities use wastewater as part of their polio eradication efforts, for example.
And while the NWSS was created as part of the COVID-19 response, the CDC is working to expand the system’s ability to track other Pathogens.
Future targets will include antibiotic-resistant germs, foodborne infections, influenza and emerging fungal pathogens, Kirby said.
Visit the COVID tracking project to see the new wastewater monitoring program.
SOURCE: U.S. Centers for Disease Control and Prevention, press briefing, February 4, 2022 with Amy Kirby, PhD, MPH, program manager, CDC’s National Wastewater Surveillance System