Science just confirmed what your sick friends have been saying: The flu shot hasn’t been all that effective lately. New research was presented at a San Diego infectious disease conference, vindicating your Facebook friends that post about the flu shot being useless. While it’s not actually useless, it’s not nearly as effective as it could be.
Boston Globe reports that a part of the vaccine that’s supposed to protect against three or four types of the flu virus — influenza A H3N2 —only reduces the risk of infection by 38%.
The parts that protect against influenza B and H1N1are much more effective, reducing the risk of infection by 60 – 75%. Unfortunately, H3N2 is a worse virus and makes people sicker.
The flu shot used to be more effective — or at least we thought it was, based on the way scientists measured success. A decade ago, research said a flu shot reduced a person’s chances of catching the flu by 70 – 90%. But, as the Boston Globe notes, “starting in about 2005, flu epidemiologists began using a new type of study design to assess the vaccine’s impact during individual flu seasons. The result: real-time estimates of how well the vaccine was working, broken down by the virus type targeted.”
So now we know how well the shot is actually working and currently, it’s not nearly as effective against the nasty strains as we might have previously believed. “Nobody responds all that well to H3N2 vaccine,” said Dr. Edward Belongia, an influenza epidemiologist at Marshfield Clinic Research Foundation. ”The vaccine has some effectiveness and 30 to 40 percent effective is better than nothing, but it’s certainly not as good as we would like to see.”
So, it’s probably smart to get your flu shot, but maybe you should only feel, say, 30 or 40% confident that it’ll work.