Purified influenza vaccine: clinical and serologic responses to varying doses and different routes of immunization.

Abstract

Recently a purified bivalent influenza vaccine prepared by zonal ultracentrifugation was described, which appeared to be highly antigenic and to cause few side reactions [1, 2]. During the 1968-1969 epidemic of influenza caused by the Hong Kong variant of influenza A2 virus, a highly purified monovalent influenza vaccine was prepared in a similar manner and made available for field testing. Because it was highly purified and could be concentrated in the zonal ultracentrifuge, the vaccine was available in preparations of different potency. This made it possible to give the vaccine at different levels of dosage and to compare antigenic response and incidence of side reactions to a single subcutaneous inoculation. Although the usual route of immunization employed with killed influenza vaccines is the subcutaneous one, physicians have frequently used the intradermal route in patients who have given a history of previous severe local reactions to the vaccine or when vaccine is in short supply. Recent reports have also suggested that administration of the vaccine intranasally may be a more effective way of obtaining local antibody and