Military Study Shows Prevention of Novel A/H1N1 Virus Infection is Vaccine-Type and Age-Dependent

WASHINGTON-PRNewswire/--Immunization with either live attenuated influenza vaccine (LAIV, also known as FluMist®), or trivalent inactivated influenza vaccine (TIV), appears to offer a protection (~ 45%) against the novel A/H1N1 virus, the cause of the present influenza pandemic. However, the benefit was largely attributed to the youngest age group. The finding emerges from an evaluation of medical encounters and seasonal influenza immunization of U.S. military service members.
As reported today in a Late-Breaker presentation at the 58th annual meeting of the American Society of Tropical Medicine and Hygiene (ASTMH), seasonal influenza vaccination also appears to offer higher protection against severe disease requiring hospitalization (~ 62%, 95% confidence interval [CI], 14% to 84%) than against milder infections that can be treated on an outpatient basis (~ 42%, 95% CI, 29% to 53%).
"The increasing momentum of the H1N1 pandemic underscores the need for vaccination, yet there is a wide variance in vaccine effectiveness depending on the strain-match for a particular season," comments Col. (Ret.) Jose L. Sanchez, MD, MPH, of the Armed Forces Health Surveillance Center (AFHSC) in Silver Spring, Maryland...

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