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March 11, 2022

This year's flu vaccine was just 16% effective, according to CDC

Daily Briefing

    The influenza vaccine for this year was around 16% effective, according to a recent report from CDC, a rate the agency said is "not statistically significant."

    Where the flu season stands now

    CDC's data shows that for the week ending in Feb. 26, 1,445 influenza cases were reported by clinical laboratories, down from 2,391 the week before, and down from a peak of 6,894 for the week ending in Dec. 25, 2021.

    However, while influenza cases have generally been dropping over the past few weeks, hospitalizations reported to HHS have risen recently.

    According to CDC, influenza hospitalizations dropped to 785 during the week ending in Jan. 29 and have since steadily risen, hitting 1,504 for the week ending in Feb. 26, up from 1,410 the previous week and the highest hospitalization rate since the week ending in Jan. 8, which saw 1,811 hospitalizations.

    CDC says flu vaccine wasn't very effective

    In its report, CDC analyzed data from 3,636 Americans in seven states who had an acute respiratory infection between Oct. 4, 2021, and Feb. 12.

    They determined the flu vaccine "did not reduce the risk for outpatient respiratory illness caused by influenza A (H3N2) viruses that have predominated so far this season" and was just 16% effective, which CDC said is "not statistically significant."

    However, CDC still recommends Americans get their flu vaccine because it could "prevent serious outcomes."

    In October and November of 2021, CDC found similar results regarding the vaccine's efficacy when investigating an influenza outbreak at the University of Michigan, finding the vaccine didn't offer much protection.

    "It's not ineffective, but it's clearly suboptimal in its efficacy," said Jesse Goodman, a former chief scientist at FDA, adding that the low efficacy rate "suggests that there was a mismatch between the strains of virus in the vaccine and what's circulating."

    Goodman added that this season's results show that flu vaccines need to be improved. "The next pandemic could be an influenza pandemic," he said, "so we need better vaccines." (Lukpat, New York Times, 3/10)

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