According to a Bloomberg analysis of Centers for Disease Control and Prevention data, a wastewater network that monitors Covid-19 trends is warning that cases are once again on the rise in many parts of the United States.
More than a third of the CDC’s wastewater sample sites in the United States showed rising Covid-19 trends from March 1 to March 10, though reported cases remained near a recent low.
The number of sites with rising signals of Covid-19 cases is nearly double what it was from February 1 to February 10, when the wave of omicron-variant cases was rapidly fading.
It’s unclear how many new infections the sewage signs represent, or whether they’ll be a new wave or just a brief blip on the way down from the last one.
People are returning to work in many parts of the country, and mask regulations have been relaxed, both of which can increase transmission.
Simultaneously, warmer weather allows people to spend more time outside, and many people have recently been infected, which may provide at least temporary protection against getting sick again – factors that would keep cases down.
“While wastewater levels are generally very low across the board, we are seeing an increase in sites reporting an increase,” Amy Kirby, the head of the CDC’s wastewater monitoring programme, told Bloomberg in an email.
“These bumps could simply be minor increases from very low levels to even lower levels. However, as prevention strategies in many states have changed in recent weeks, some communities may be seeing an increase in Covid-19 infections.”