How effective is the flu vaccine?
Studies have indicated that influenza vaccine efficiency is approximately 70%-90% effective in preventing illness among persons 65 years of age or less. It is 30%-40% effective among the frail elderly, 50%-60% effective in preventing hospitalization, and approximately 80% effective in preventing death. The degree of effectiveness is dependent on a good match between the circulating influenza strains and the components included in the influenza vaccine each year. It also depends on the ability of each person’s immune system to effectively produce an antibody against the virus.
