US flu activity down for second week, CDC data show

Flu activity drops, but experts warn the season is not over

The U.S. flu season appears to be waning, with measures of flu activity declining for a second straight week, according to the Centers for Disease Control and Prevention’s latest data released Friday. The CDC said flu hospitalizations dropped sharply and flu-like illness visits to medical offices also fell.

The CDC also reported that the number of states seeing high flu activity decreased, falling from 44 to 36. The agency said there have not been large surges in two other winter respiratory threats, COVID-19 and RSV.

CDC officials characterized the current respiratory virus season as “moderate,” but they cautioned that the season is not necessarily finished—especially for flu. The CDC noted that second surges in flu activity often occur after the winter holidays.

Concern centers on an H3N2-dominated season

Medical experts said concern about the season has been driven by the type of flu virus circulating most widely. They said the season has been dominated by an H3N2 virus that historically causes the most hospitalizations and deaths in older people.

The AP reported that about 90% of the H3N2 infections analyzed this season involved a new strain that differs from the version accounted for in this year’s flu shots. That mismatch, experts said, is part of why they have been worried even as some measures have declined.

CDC estimates: millions of illnesses and thousands of hospitalizations and deaths

So far this season, the CDC estimated there have been at least 18 million flu illnesses and 230,000 hospitalizations, AP reported. The agency also estimated there have been 9,300 flu deaths so far, including at least 32 children.

For those children whose vaccination status is known, the CDC estimated that 90% were not fully vaccinated against flu. Even with early declines in multiple indicators, experts said those figures underline the potential for continued illness as the season progresses.

Doctor warns against relying on early abatement

Dr. William Schaffner, an infectious diseases specialist at Vanderbilt University in Tennessee, said flu seasons can peak and then still last longer than people may expect.

“We’ve had other seasons where we’ve had a peak, it’s gone down, but we’ve nonetheless had a prolonged season,” Schaffner said, according to the AP. “Most of us are crossing our fingers,” he added. “But I don’t think we can rely on the concept that flu is abating very early this year.”