Here are the latest national COVID-19 trends, according to the U.S. Centers for Disease Control and Prevention (CDC) and major wastewater surveillance providers:
- About 0.7 in every 100,000 people were hospitalized for COVID-19 during the week ending March 28.
- COVID-19 test positivity decreased slightly, from 2.3% of COVID-19 tests returning positive results during the week ending March 21 to 2.1% positive during the week ending March 28.
- SARS-CoV-2 concentration in wastewater decreased 1% between March 21 and March 28, and the national wastewater viral activity level is “very low,” per the CDC.
- SARS-CoV-2 concentration in wastewater decreased 11% between March 18 and March 25 and the national wastewater trend is “medium,” per WastewaterSCAN.
COVID-19 levels are low to moderate across most of the U.S., as we are in a lull between waves. But they are unlikely to get much lower without widespread public health measures. And the variant BA.3.2 (“Cicada”) may be starting to drive increased spread in parts of the Northeast.
Wastewater surveillance data from the CDC and WastewaterSCAN report relatively low national averages of SARS-CoV-2 in U.S. sewage as of late March. The CDC’s national average stayed consistent in its most recent two weeks of data, while WWSCAN’s went down slightly. As I noted last week, WWSCAN’s recent national averages are below the lowest points of most lulls between surges in 2023-2025, but still several times higher than the true points of low spread we experienced early in the pandemic.
However, as infectious disease modeler J.P. Weiland pointed out on social media, these trends can be difficult to interpret even from a source like WWSCAN with consistent reporting: it’s possible that SARS-CoV-2 levels during individual COVID-19 cases have shifted as the virus has evolved, and the ratio of viral levels to actual infections may be higher or lower than it used to be. (This is one reason why I do not cite estimates that claim to “translate” wastewater levels to estimated infections.)
At the regional level, WWSCAN and the CDC both report potential COVID-19 outbreaks in the Northeast, while the CDC also reports a potential increase in the South. As is often the case for the CDC’s wastewater levels, though, it seems this increase in the South may be driven by a few states with limited testing sites (Tennessee, Mississippi, Louisiana) rather than being a true reflection of trends across the region.
The CDC’s test positivity data report a very low national average for COVID-19 and declines or plateaus in most regions. But there is a notable exception in the Northeast — specifically in health region 2, which includes New York and New Jersey. In WWSCAN’s data, a testing site in Oswego, New York jumps out with particularly high SARS-CoV-2 levels. As data tracker Patrick Vaughan flagged, New York has also been a site of BA.3.2 (“Cicada”) detections recently, suggesting that this variant could be behind the increase.
Like other metrics, the CDC’s infectious disease forecasting center reports widespread declines in COVID-19 spread: the center estimates that cases are “declining or likely declining” in 32 states and not growing in any states as of March 31. Notably, though, the center did not estimate a trend for New York State this week due to limited data.
Variant experts continue to closely watch BA.3.2, or “Cicada.” It is still spreading in the U.S. in relatively low levels compared to other SARS-CoV-2 variants; in fact, the CDC’s estimate of BA.3.2 in wastewater declined slightly between March 21 and March 28. But the U.S. is doing much less genomic surveillance now than we did earlier in the pandemic, making trends harder to follow. Even with the limited data we have, it’s becoming evident that BA.3.2 cases are more common in children compared to past variants, at least so far.
