Just one I plucked from the web....
"The researchers, led by Dr. Tom Jefferson, a British epidemiologist and chief of the Vaccine Field Group at Cochrane, reviewed studies conducted between Jan. 1, 1966, and June 2010. The authors included 50 reports, of which 40 were clinical trials involving more than 70,000 people.
What they found was shocking. When the vaccination matched the viral strains actually circulating that season, with a high circulation - an uncommon occurrence - 4 percent of unvaccinated people developed symptoms compared with 1 percent of vaccinated people. In the more common years where vaccines did not match the circulating strain, two percent of unvaccinated people got the flu compared with 1 percent of those vaccinated.
In testimony earlier this year before the Parliamentary Assembly of the Council of Europe, Jefferson put those numbers in perspective.
"After reviewing more than 40 clinical trials, it is clear that the performance of the vaccines in healthy adults is nothing to get excited about," Jefferson said.
"On average, perhaps one adult out of a 100 vaccinated will get influenza symptoms compared to two out of 100 in the unvaccinated group. To put it another way, we need to vaccinate 100 healthy adults to prevent one set of symptoms."