Source Huffington Post
Flu vaccine is not as effective as public health messaging traditionally has claimed, says a new report that suggests overselling of flu shots is getting in the way of developing more effective and longer lasting vaccines.
The project that led to the report was called the CIDRAP Comprehensive Influenza Vaccine Initiative, and it involved mining more than 12,000 documents, articles and meeting transcripts as well as more than 5,700 peer-reviewed vaccine studies published from 1936 through April 2012. The full report can be found here.
In recent years studies by a variety of research groups have shown that the long-quoted claims that flu shots offered 70 to 90 per cent protection against influenza have been off the mark.
Somewhere in the order of 50 to 60 per cent, in healthy adults, is more accurate, the newer studies suggest. Efficacy rates are lower in the elderly or people in poor health. Vaccine effectiveness in those 65 and older against both influenza A and B was 27% (95% CI, -31% to 59%), and against H3N2 it was 9% (95% CI, -84% to 55%), but both numbers are statistically not significant.
The report suggests that the higher numbers came from old studies done on vaccines that were not formulated the way current shots are. It also suggests that the belief that universal vaccination for flu would be useful and desirable, rather than solid scientific evidence, was what drove decisions to recommend flu shots for all in the U.S. (The study did not look at decisions made in Canada or elsewhere.)
Even the vaccine used in the U.S. during the 2009 pandemic — where there was a perfect match between the virus in the vaccine and the strain infecting people — didn’t offer better protection. Studies cited in the report pegged the U.S. vaccine’s effectiveness at 56 per cent.
A key argument of the report is the fact that the current vaccine that offers moderate protection is actually getting in the way of developing long-lasting flu vaccines that offer more effective protection — vaccines, for example, that might require a shot every five or 10 years. Currently flu shots are reformulated every year to try to keep up with the evolution of flu viruses.
Even though a flu shot is a relatively inexpensive vaccine, manufacturers sell hundreds of millions of doses of them a year. In fact, the report notes that the global market for flu vaccine is estimated at US$2.8 billion — a decent chunk of the estimated US$20 billion annual market for all vaccines combined.
For an interesting article of influenza and the protectiveness of Vitamin D please read On the epidemiology of influenza