COVID-19 cases are on the rise again across the United States, with the biggest increases in parts of the South, Southeast and West Coast.
The U.S. Centers for Disease Control and Prevention (CDC) estimates that 25 states are seeing growth in COVID cases as a summer wave appears to be starting, CBS News reported.
Even though activity remains “low” nationwide — based on CDC wastewater data — it’s up from “very low” the week before.
Some of the biggest increases in emergency room visits for COVID have happened in the Pacific Northwest and the Southeast. In those areas, rates are now the highest they’ve been since February and March, CBS News added.
Health experts had been watching for a possible summer spike, as new versions of the virus spread across the country.
A recent CDC analysis shows that COVID now seems to follow a twice-a-year pattern: Cases usually peak once in the summer (July through September) and again in the winter (from December through February).
"Our analysis revealed biannual COVID-19 peaks in late summer and winter, a pattern that is expected to persist as long as the rapid evolution of SARS-CoV-2 and cyclical S1 diversity continues," CDC scientists wrote.
S1 diversity refers to ongoing changes in a key part of the virus’s spike protein — specifically the S1 region, which helps the virus bind to human cells, CBS News reported.
The CDC is also warning about another virus that’s spreading more than usual right now: Parvovirus B19.
Most people who catch this virus don’t get very sick. But some develop flu-like symptoms, including fever, muscle aches and a rash.
Pregnant women are at higher risk for complications from parvovirus B19. The CDC says they should take extra steps to protect themselves such as wearing a mask in high-risk places.
In Chicago, health officials said emergency rooms are seeing a spike in patients with this virus.
"Several of the most recent weeks saw the highest percentage of B19-associated ED visits compared to the same week in all years since 2015," health officials said.
Parvovirus B19 is not the same parvovirus that infects dogs and other canines.