Acceptibility and antigenicity of influenza A/Victoria/75 virus vaccines in adults of different ages.

Influenza A/Victoria/75 virus vaccines were tested for acceptability and antigenicity in adults of different ages. Whole-virus vaccines prepared by Merck Sharp and Dohme (West Point, Pa.) and Merrell-National Laboratories (Cincinnati, Ohio) and subunit vaccines prepared by Parke, Davis and Company (Detroit, Mich.) and Wyeth Laboratories (Philadelphia, Pa.) were given intramuscularly in concentrations of 800, 400, or 200 chick cell-agglutinating units per dose. Systemic and local side effects of all vaccine preparations were negligible. In volunteers with low or absent (less than or equal to 10) titers of hemagglutination-inhibiting antibody before vaccination, titers of greater than or equal to 40 were attained after vaccination in 43%-67%, 40%-58%, and 20%-38% of volunteers receiving the 800, 400, and 200 chick cell-agglutinating unit preparations, respectively.