Daily cases counts have increased 38% in the past week, according to the latest data from the U.K. Health Security Agency. Hospitalizations are up about 25% as well.
“Over the last year or so, what happens in the U.K. usually happens here a few weeks later,” Anthony S. Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, told NPR.
“And right now, the U.K. is seeing somewhat of a rebound in cases,” he said.
Health officials in the United Kingdom have noted the latest increase is likely due to the contagious BA.2 Omicron subvariant, the recent loosening of coronavirus restrictions, and waning immunity from vaccinations and infections.
“All three of those factors we have here in the United States,” Dr. Fauci said. “So I would not be surprised if, in the next few weeks, we see either a plateauing … of cases or even [the curve] rebounds and slightly goes up.”
Right now, COVID-19 cases in the United Stastes have dropped to their lowest levels since July 2021, according to the latest Centers for Disease Control and Prevention data, with fewer than 30,000 daily cases. At the same time, the rate of decline in cases has slowed significantly and is beginning to plateau.
Public health experts are also pointing to wastewater surveillance data that shows an uptick in viral activity across the country. The CDC’s wastewater dashboard indicates that about 35% of sites that monitor wastewater are seeing an increase, with consistent growth in Florida, Rhode Island, and West Virginia.
“The power of wastewater surveillance is that it’s an early warning system,” Amy Kirby, the program lead for the CDC’s National Wastewater Surveillance System, told NPR.
“We are seeing evidence of increases in some communities across the country,” she said. “What looked like noise at the beginning of the week is starting to look like a true signal here at the end of the week.”
The wastewater system doesn’t distinguish between Omicron and subvariants such as BA.2. However, other CDC data has found an increase in BA.2 cases in the United States, making up about a quarter of new COVID-19 cases.
The BA.2 variant has roughly doubled each week for the last month, which means it could become the dominant coronavirus strain in the United States in coming weeks, according to USA Today. Cases appear to be spreading more quickly in the Northeast and West, making up about 39% of cases in New York and New Jersey last week.
BA.2 also accounts for nearly 39% of cases across the Northeast, including Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island and Vermont, USA Today reported. In the West, which includes Arizona, California and Nevada, the subvariant makes up about 28% of new cases. In the upper West, which includes Alaska, Oregon and Washington, about 26% of cases are BA.2.
The good news is that BA.2 “doesn’t seem to evade our vaccines or immunity any more than the prior Omicron [variant]. And it doesn’t seem to lead to any more increased severity of disease,” Rochelle Walensky, MD, the CDC director, told NPR’s Morning Edition on March 18.
The effects of BA.2 will likely depend on the immunity profile in the United States, including how long it’s been since someone was vaccinated, boosted, or recovered from an infection, she said.
Health officials are watching other countries with BA.2 increases, such as Germany, Italy, and the Netherlands. Many European countries have been reporting an uptick but not implementing major restrictions or shutdowns, USA Today reported.
The BA.2 variant likely won’t lead to a major surge in severe disease or strict COVID-19 measures, Dr. Fauci told NPR, but some coronavirus protocols may need to be implemented again if cases grow dramatically.
“We must be ready to pivot and, if necessary, to go back to stricter mitigation with regard to masks,” he said.
A version of this article first appeared on WebMD.com.