Flu vaccine worked well in season that faded fast, CDC says
NEW YORK — Early estimates suggest the flu vaccine performed well in a U.S. winter flu season that has already dissipated.
The vaccines were more than 40% effective in preventing adults from getting sick enough from the flu that they had to go to a doctor’s office, clinic or hospital, health officials said during a Centers for Disease Control and Prevention vaccines meeting Wednesday. Officials generally are pleased if a flu vaccine is 40% to 60% effective.
One reason is the vaccine was a good match against the strains that spread over the fall and winter, officials say.
About half of eligible kids and just under half of adults got flu shots in the last several months, according to CDC data. Vaccination rates were up compared with 2021-2022, but below what they were before the
COVID-19 pandemic hit in 2020, said the CDC’s Brendan Flannery.
Initially, it looked like it might be a bad flu season. The virus took off in early November as COVID-19 and another respiratory virus, RSV, roiled emergency departments. Among kids, flu-related hospitalization rates in November and December were as high as any seen in recent years, Flannery said. At least 111 flu deaths have been reported in children, the most since the 199 reported in the 20192020 season.
The dominant flu strain was the kind typically associated with higher rates of hospitalizations and deaths, particularly among older people. In some years, the vaccines were virtually ineffective against that strain in people 65 and older. But this season’s vaccine produced the best results seen in at least 10 years, said Flannery, who is responsible for the CDC’s flu vaccine effectiveness data.
Flu also apparently made a very early exit, with the virus declining since the end of November. Some pockets of high flu activity have persisted this month, including in New Mexico and New York City. But for the vast majority of the country, it’s low.
It’s not clear exactly why the wave crested so early, but flu seasons have been unusually mild or otherwise strange since the COVID19 pandemic started three years ago, Flannery said.