Vaccinating against influenza

Japan is the only country that has ever had the policy of controlling the toll of influenza by immunizing schoolchildren rather than the elderly. This policy gained advocates after the deadly Asian flu outbreak in 1957, became more commonly practised from 1962 through 1977, and was made mandatory from 1977 until the laws were relaxed in 1987 and ultimately revoked in 1994.

From 1962 through 1987 most Japanese schoolchildren, perhaps up to 80% in the 7 to 15 year old age group, were vaccinated against influenza; after 1994, this percentage fell to very low levels. Excess mortality (death rates) from pneumonia, influenza and all-causes in Japan were highly correlated with children's vaccination rates. By comparison, these rates remained fairly constant over the same time period in other countries. With the growing implementation of the vaccination programme in Japan, excess mortality rates dropped over three-fold those in comparable countries. It is estimated that the children's vaccination programme prevented between 37,000 and 49,000 deaths per year in Japan, or 1 (adult) death for every 420 child vaccinated. As children's vaccination rates fell after 1987, the excess mortality rates for each of the parameters evaluated increased. This seemingly effective law was revoked because there were sensationalized reports of lawsuits alleging adverse side effects of vaccination, and the public lost confidence in the programme.

A similar effect was found during the 1968-9 "Hong Kong Flu" outbreak in Tecumseh, Michigan, USA when that community achieved a vaccination rate of 85% of its schoolchildren. The data, analysed and published in 1970, showed that the adult rate of influenza was one-third of that in a neighbouring region where children remained unvaccinated.