June 27, 2019
The 2018-2019 flu season was a particularly rough one in the United States, with a death toll of close to 57,000.
A report released Thursday suggests this year’s vaccine — which has a varying formula each year to protect against the different flu strains projected to be active — wasn't very effective against a bug that popped up halfway through the flu season, according to the Associated Press.
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The vaccine only proved to be 29 percent effective overall during the season, the AP reported:
The flu shot was working well early in the season with effectiveness put at 47% in February. But it was virtually worthless during a second wave driven by a tougher strain, at just 9%.
This season’s shot turned out to be a mismatch against the bug that showed up late.
According to the CDC, flu vaccines generally protect against three to four viruses, depending on those circulating. This season saw a three-component vaccine, composed of two variations of the A strain of the flu and one of the B.