The Big Story Blog

Research forces a new look at flu vaccines

Posted at 6:20 AM on October 26, 2011 by Paul Tosto
Filed under: Health

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(MPR Photo/Nikki Tundel)

It's been the shot for decades. The influenza vaccine is an annual right of passage for millions of people. It's turned into a civic duty of sorts and it's hard not to feel a little bit invincible after you get it.

Turns out, though, it's not quite the armor we thought.

News came late Tuesday that research led by the University of Minnesota shows flu vaccines work on only about 59 percent of the population -- far less than previously believed-- and that children and seniors may benefit the least.

We'll take a deep look today at the research and news around the flu vaccine and its effectiveness. Post below with any questions or insights or contact us directly.

Here are some of the things we know this morning.

1.) The efficacy of flu vaccines may be vastly overestimated. The findings of University of Minnesota infectious disease expert Michael Osterholm and three other national flu researchers screened thousands of flu studies published since the 1960s "and found only a handful that adequately measured the effectiveness of flu vaccine. They say most of the published studies vastly overestimated the benefits of receiving the vaccine," MPR News reporter Lorna Benson writes.

Past studies have showed vaccine to be 70 percent to 90 percent effective in preventing flu in healthy adults. The Osterholm paper says 59 percent is closer to reality.

2.) Flu spray may not work. Besides the shot, researchers also questioned the nasal spray version of the vaccine. The Star Tribune reports:

Flu vaccines may have had little, if any, effect during some flu seasons, according to the report...The most common flu shot, which uses an inactivated flu virus, had no noticeable impact in four out of 12 seasons studied. The nasal spray version, which is made with a live virus, had no apparent effect in three out of 12 seasons.

3.) 59 percent is better than nothing. You may hear a lot in coming days from anxious public health officials worried the latest research will convince the public a flu shot isn't worth it. That's the message even from those who were part of the U-led study.

Minnesota state epidemiologist Kris Ehresmann says the research still demonstrated that the vaccines work for many people. That's the point she'll continue to make to the public.



About Paul Tosto

Paul Tosto

Paul Tosto writes the Big Story Blog for MPR News. He joined the newsroom in 2008 after more than 20 years reporting on education, politics and the economy for news wires and newspapers across the country.