NEW YORK — The U.S. flu season is off to a slow start, and it's unclear whether it will be as severe as last winterHowever, some health experts are concerned that data from the US Centers for Disease Control and Prevention released on Friday shows that a new version of the virus has emerged.
Early analysis suggests current vaccines may still be somewhat effective against the new version of the flu, which has become a leading cause of recent infections, CDC data shows.
Some scientists and health care workers are more concerned about disappointing vaccination rates, a major reason why flu hospitalizations and deaths were unusually high during last year's flu season, one of the deadliest this century.
“I think we're in for a really tough season,” Faraz Covelli of the George Washington University School of Nursing told Asefa.
Last winter, overall flu hospitalization rates were the highest since the H1N1 flu pandemic 15 years ago. Flu was the underlying or contributing cause of more than 18,000 deaths, and in one seven-day period earlier this year more than 1,800 deaths were reported – the highest weekly spike in at least a decade. Mortality from childhood flu were also much higher than usual.
CDC data Friday's report showed low flu activity, with only one state, Louisiana, reporting moderate activity. Most reported infections are in children, said Alicia Budd of the Centers for Disease Control and Prevention (CDC), who tracks flu cases for the Atlanta-based agency.
Most were also a new version of the H3N2 type A virus, which has historically caused the most hospitalizations and deaths among older adults. This type is responsible for the majority of flu infections this year, and more than half of them are a new subclade K variant that is different from the strain that this year's flu shots were designed to combat.
Preliminary analysis from the United Kingdom suggests the vaccines do provide at least partial protection, although it will take some time for scientists to know exactly how effective they are. Experts say it's important to provide any protection that softens the blow of a flu infection.
Flu seasons tend to get worse between December and February, and illnesses are likely to increase as people travel and gather for Thanksgiving, Covelli said.
“I think this is where things will start to pick up steam,” she said. “This is the perfect time to get vaccinated.”
Researchers have faced an unusual struggle this year to understand trends in respiratory infections and vaccination rates.
They typically rely on data from the Centers for Disease Control and Prevention (CDC), but the recent government shutdown stopped data collection and reporting just as respiratory infections began to rise.
Meanwhile, government efforts to promote preventive vaccinations have become more limited since U.S. Secretary of Health Robert F. Kennedy Jr. was appointed to lead the Centers for Disease Control and Prevention (CDC) and other federal health agencies. Kennedy, a leading anti-vaccination activist, has increased uncertainty about the safety of vaccines, including flu shots that contain a preservative called thimerosal.
Indeed, vaccination rates against COVID-19 clearly continue to fall sharply: according to other CDC data published on Friday. Each figure is about 3 percentage points lower than it was at this point last fall.
When it comes to influenza, vaccination trends are a little more confusing. Some sources suggest that flu vaccinations have declined. Through the end of October, more than two million fewer flu shots were administered at U.S. pharmacies than last year, according to IQVIA, a health information and research company.
But the latest CDC data shows the childhood vaccination rate this year is about the same as last fall, at 34%. And the vaccination rate among adults rose several percentage points to about 37%, according to Centers for Disease Control and Prevention (CDC) data based on survey data.
It's still early in the season and it's too early to tell whether the increase will be sustained or what's causing it, the CDC said.
As of early November, flu hospitalization rates in the United States are about the same as they were at the same point in 2024. one more set CDC data.
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