CBS News – This season’s influenza vaccine may have been a poor match to a strain of the flu virus that caused many infections this winter, early data released by the Centers for Disease Control and Prevention suggests.
The CDC’s latest data come as much of the U.S. is finally seeing signs of a slowdown in influenza activity after waves of illness this past fall and winter that climbed to the worst rates recorded from hospitals and doctor’s offices since the 2009 swine flu pandemic.
“This is a bad year, no doubt about it,” Dr. Jon LaPook, CBS News chief medical correspondent, told “CBS Mornings” on Tuesday.
Up to 910,000 hospitalizations are estimated to have been caused by the flu since October 2024, which puts the season on track to be the most severe in at least a decade.
“Depending on the strain, depending on what’s going on, it could really vary. And this year is brutal,” said LaPook.
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Every season, the CDC’s scientists test a sample of flu viruses collected from labs around the country against strains that health authorities had picked out for use in the latest update to the annual flu vaccine.
“CDC antigenically characterizes about 2,000 flu viruses during a typical flu season to monitor for changes in circulating viruses and to compare how similar these viruses are to those included in flu vaccines,” Paul Prince, a CDC spokesperson, said in a statement.
Many of the flu viruses that the CDC has tested this season were “well-recognized” by antibodies targeted to the vaccine, which helps the body fight off the infection, the agency reported this month.
The testing is done using antibodies from ferrets, which have similar influenza symptoms to humans …