Here are the latest national Covid-19 trends, according to the CDC and major wastewater surveillance providers:
- New hospital admissions with Covid-19 have decreased 14%, from 1,600 admissions per day during the week ending March 16 to 1,300 admissions per day during the week ending March 23.
- Test positivity has decreased 13%, from 4.6% of Covid-19 tests returning positive results during the week ending March 16 to 4.0% of tests during the week ending March 23.
- Healthcare visits for influenza-like illness have decreased 10% between the week ending March 16 and the week ending March 23.
- SARS-CoV-2 concentration in wastewater has decreased 18% between the week ending March 16 and the week ending March 23, and the national wastewater viral activity level is low, per the CDC.
- SARS-CoV-2 concentration in wastewater has decreased 7% between March 23 and March 30, per Biobot Analytics.
- SARS-CoV-2 concentration in wastewater has remained consistent between March 18 and March 25, per WastewaterSCAN.
All national Covid-19 and respiratory illness metrics suggest that disease spread continues to trend down across the U.S., following the same pattern we’ve observed over the last month. However, wastewater data suggest that SARS-CoV-2 transmission may be heading for a plateau as the virus continues to evolve.
Wastewater surveillance data from the CDC, which has the most comprehensive representation of sewage testing across the U.S., shows continued declining SARS-CoV-2 levels in wastewater at the national level as of March 23. But Biobot Analytics and WastewaterSCAN, the two other major national dashboards — which provide more recent data, as of March 30 and March 25, respectively — suggest that this decline in coronavirus spread is slowing down, likely turning into a plateau.
We’ll have to watch for continued changes in wastewater data over the coming weeks. The Northeast may be particularly worth watching: the CDC and Biobot report that coronavirus spread has leveled off in this region, while WastewaterSCAN reports increased SARS-CoV-2 in the last week. Boston’s local wastewater dashboard similarly reports recent increased virus in both city sewersheds; we have less visibility for New York City, which hasn’t provided updated wastewater data in the last month.
Covid-19 hospitalizations and test positivity continue to decline nationally and across all regions, with hospitalizations at the lowest level we’ve seen since last summer. (Note: these healthcare system metrics are delayed by a couple of weeks compared to wastewater.) The CDC reports declining respiratory viruses (flu, RSV, common colds, etc.) as well. Most states reported moderate or low influenza-like activity levels in the week ending March 23, with the exception of a few in the Midwest and West: New Mexico, Wyoming, Nebraska, North Dakota, Michigan.
Variants provide one possible reason why Covid-19 might soon be spreading more in some parts of the country. The JN.1 lineage, which drove this past winter’s surge, has further evolved into a new variant called JN.1.13. JN.1.13 caused about 10% of new infections in the U.S. during the two weeks ending March 30, according to the CDC — and caused 20% of new cases in the New York/New Jersey region. Scientists are closely watching this variant, as it has mutations that could enable faster spread.
Speaking of viruses evolving: health officials in Texas recently identified a person who became infected with H5N1, the bird flu, after contact with dairy cows. This is an isolated case so far, but the CDC and state health agencies are monitoring for further infections. If the flu virus spreads more widely, it could present a new test of the U.S.’s pandemic preparedness — and some experts suggest we aren’t ready.
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