And is the Seasonal Flu Shot Effective?

Today's Toronto Star (registration required) reports on a recent Cochrane Collaboration review of the annual flu shot Americans are encouraged to take. It found that universal innoculation was not supported by the evidence. The Cochrane Collaboration is an international non-profit that analyzes the effectiveness of health care interventions.

According to the Star, a Cochrane group "reviewed 12 randomized control trials of the impact of the flu vaccine on healthy adults under 65 found it didn't meet any of its specific goals — to reduce the spread of the disease, the number of days lost from work or deaths and hospitalization from it."

On the other hand, the review found 19 per cent of those who had a flu shot got sick with influenza, compared with 23 per cent of those who didn't. That level of protection would be significant if the flu involved had a high mortality ratio. The avian flu strain H5N1, though not easily transmissible from person to person, has nearly a 50 percent mortality rate.