"Some evidence also suggests vaccines may not even be as effective against flu viruses as advertised. A review of the scientific literature by Tom Jefferson, an epidemiologist at the Cochrane Collaboration in Britain, finds little scientific data to support the effectiveness of flu vaccines in reducing infection or death. Jefferson told TIME in February that "we don't know what protection, if any, [flu] vaccines offer."
From Time magazine http://www.time.com/time/health/article ... -4,00.html
Read more: http://www.time.com/time/health/article ... z13mKX42xg