Vaccination in the control of influenza.

Although killed influenza vaccine given by injection is protective, able to reduce sickness absence in industry and to control influenza in the armed forces, it has not so far been possible to demonstrate more than a small effect on the disease in otherwise healthy adults in industry and offices in the United Kingdom. The reasons are probably the poor rate of acceptance of vaccine, the relatively low incidence of clinical influenza in most years, and the incomplete protection given by the vaccine. Until major epidemics can be accurately forecast it is suggested that influenza vaccination may most usefully be used on a selective basis, namely for protecting those with illness predisposing to a severe effect from influenza; persons in institutions such as schools and homes for the elderly; key workers in the general population; and persons over the age of 65 years among whom considerable mortality occurs in winters when influenza is prevalent.