A Hidden Benefit from a Flu Shot

Now’s the time of year to get your flu shot (if you haven’t had one already). And it’s just been reported that the shot can protect you from another risk – having a venous thrombotic embolism. This news emerged at the American Heart Association meeting in New Orleans. Dr Joseph Emmerich of the University of Paris described his study of the possible link between a flu shot and venous thrombosis.

Over 700 patients who were hospitalized with for a first episode of deep venous thrombosis or a pulmonary embolism were asked if they had had a flu shot in the last year. They were compared with an equal number of control subjects, matched for gender and age, who were also hospitalized but without thrombotic disease.

After factors such as body weight, oral contraceptive use, and varicose veins had been controlled for, having a flu shot was linked with a 26% reduction in the subsequent risk of having a venous thrombosis episode. The reduction was actually 48% in those patients younger than 52, which was the average age of the persons in the study.

The researchers hadn’t designed the study to find out why (or how) flu vaccination reduces the risk of venous thrombosis. One theory mentioned was that ‘protected’ patients might spend fewer days ill in bed (a known cause of thrombosis). Or perhaps an infection like influenza has a direct pro-thrombotic influence. Either way, it’s a positive finding that should encourage those doubters to go to the flu-shot clinic, straight away.