Just as the United States sheds masks and eases pandemic restrictions, there has been an uptick in the presence of COVID-19 in wastewater samples, according to government scientists.
Sewage is able to detect the presence of COVID-19 about a week before PCR testing can due to those who have been infected shedding the virus in sewage pipes several days before they show symptoms.
Bloomberg notes that a third of the agency’s wastewater sample sites showed a rise in COVID cases from March 1 to March 10. The Centers for Disease Control and Prevention has since acknowledged the increase.
The increase is double what it was from February 1 to February 10 when cases of the Omicron variant started to wane.
Cause for concern?
“While wastewater levels are generally very low across the board, we are seeing an uptick of sites reporting an increase,” Amy Kirby, who heads the CDC’s wastewater monitoring program, said in a statement. “These bumps may simply reflect minor increase from very low levels to still low levels.”
“Some communities though may be starting to see an increase in COVID-19 infections, as preventions strategies in many states have changed in recent weeks," Kirby adds.
One important thing to note is that the CDC's testing program is limited to areas that collect and report on wastewater surveillance, so this isn't a national representation of the COVID spread, according to the agency.
Therefore, whether or not this is a cause of concern, remains unclear at the time.
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“It’s too early to know if this current trend will continue or whether we’ll see a corresponding increase in reported cases across the country,” Kirby shares.
“It could be that we have a new surge, a new variant in the future, and we may recommend or require universal masking in indoor public spaces again,” Contra Costa County Dr. Ori Tzvieli says.
For Dr. Sadiya Khan, an epidemiologist at the Northwestern University Feinberg School of Medicine, however, the findings are cause for “grave concern.”
RELATED: What You Need to Know About the Omicron BA.2 Subvariant
Omicron subvariant
“This increase is not a surprise and is of grave concern given the loosening of restrictions for activities and masking in schools and communities,” Khan said in an email. “If you look at patterns in Europe, there has been an increase in the last few days as well. If we’ve learned anything in this pandemic, it is that the trends in Europe precede our own.”
The increase Khan is referring to is the surge in the subvariant, Omicron BA.2, which has spread rapidly throughout Europe. Despite cases steadily going down in the U.S., public health officials have been warning Americans about the subvariant.
“We are keeping a close eye on it. It’s very hard to predict what will happen, but recent wastewater sampling suggests this subvariant is accounting for about half the cases in our county so far, and we’re also doing whole genome sequencing as well to monitor the situation,” Dr.Tzvieli adds.
“Week-over-week, every week, its a higher percentage of the cases, and we are concerned that this may lead to an increase in cases, hospitalizations or even deaths in the coming weeks,” he adds.
Taking precautions
“The response shouldn’t be alarm, but should focus on the things that work: masking and vaccines/boosting,” Khan adds. “I am not giving up my mask anytime soon.”
Cynthia Gibas, who heads the wastewater surveillance program at the University of North Carolina at Charlotte, shares that sentiment.
"We shouldn't be in panic mode about this, but we should watch it very carefully over the next few days," Gibas told NBC News.
Testing, social distancing and getting vaccinated still remain the best precaution against COVID.
Currently, 81 percent of the U.S. population is vaccinated against COVID-19, according to the CDC.
"Even if suddenly more people start just feeling the need to get tested, that is an indication that maybe something's happening," Gibas says.
For more information about getting vaccinated, visit the CDC.
