[Problems of influenza immunization and it's future]

Influenza killed vaccine were used all over the world. In Japan originally used for the children at elementary school and middle school. The purpose is that these age are frequent contact of each other and they bring back to their home influenza virus. However there are many opinion against efficacy of influenza vaccine. Then Ministry Health and Welfare decided that influenza vaccine should be use as a optional vaccine. At that time, we recommended that the high risk group should continue this vaccine. Recently, Japanese old age people lives in old-people's home. New problems comes up, how to protect them from sever influenza infection and complications. From our data, it is better to continue influenza vaccine once a year.