Meta-analysis links flu vaccine to lower risk of heart attack and stroke

The discovery of a correlation between the flu vaccine and decreased risk of heart attack was met with skepticism earlier this year, particularly in light of GlaxoSmithKline's ($GSK) financial support of the study. But now, several months later, a new, more definitive analysis has identified the same trend.

Writing in the Journal of the American Medical Association, a global team of researchers reported that their meta-analysis of 6 randomized controlled clinical trials linked flu vaccines to a lower risk of heart attacks and other major cardiovascular events. The association was particularly pronounced among patients that were considered high risk because of their active coronary disease. Among patients who had recently suffered a heart attack, administration of the flu vaccine was associated with a 55% drop in the risk of a further major cardiac event.

In the broader patient population, the use of the vaccine was linked to a 36% fall in the risk of having a heart attack, stroke or other major cardiac event. A causal relationship is yet to be established--and was never one of the goals of the meta-analysis--but the team believe the data are a compelling indication the flu vaccine is having an effect. More work is needed to confirm cause and effect, though. "We would like to do a randomized clinical trial so that a skeptical public can put the issue to rest," lead author Dr. Jacob Udell told HealthDay.

In an accompanying JAMA editorial, PATH's Dr. Kathleen Neuzil dissects the meta-analysis before calling for healthcare professionals to push for 100% vaccination of their communities. For some, the potential to cut the risk of heart attack could prove more compelling than flu prevention. "People who don't like vaccines probably don't like dying from heart attacks either. Maybe this is a good enough reason for the skeptics to go and get their flu shots," Udell told The New York Times.

Udell was funded by two Canadian research institutions, although several of his collaborators report receiving grant funding from Big Pharma companies including AstraZeneca ($AZN), Merck ($MRK) and Sanofi ($SNY).

- read the HealthDay article
- check out the NYT post (sub. req.)
- here's the JAMA paper
- and the linked editorial (sub. req.)

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