Flu vaccine only 23% effective, study finds

Associated Press

NEW YORK

This year’s flu vaccine is doing a pretty crummy job. It’s only 23 percent effective, which is one of the worst performances in the past decade, according to a government study released Thursday.

The poor showing is primarily because the vaccine doesn’t include the bug that is making most people sick, health officials say. In the past decade, flu vaccines at their best were 50 to 60 percent effective.

“This is an uncommon year,” said Dr. Alicia Fry, a flu-vaccine expert at the Atlanta-based Centers for Disease Control and Prevention, who was involved in the study.

The findings are not surprising, though. In early December, CDC officials warned the vaccine probably wouldn’t work very well because it isn’t well matched to a strain that’s been spreading widely.

Each year, the flu vaccine is reformulated, based on experts’ best guess at which three or four strains will be the biggest problem.

Those decisions usually are made in February, months before the flu season, to give companies that make flu shots and nasal-spray vaccine enough time to make enough doses.

But this year’s formula didn’t include the strain of H3N2 virus that ended up causing about two-thirds of the illnesses this winter. And that strain tends to cause more hospitalizations and deaths, particularly in the elderly, making this a particularly bad winter to have a problem with the flu vaccine.