• Clinical reactions and hemagglutinating-inhibiting (HAI) antibody responses to recent whole-virus and split-product influenza vaccines were studied in 168 children and young adults. The subjects initially received a monovalent vaccine, followed one month later by a trivalent preparation. The reactogenicity of whole-virus and split-product vaccines with an equivalent hemagglutinin content was similar except in the youngest age (6 to 36 months) group in which the whole-virus preparation was more reactogenic. The whole-virus vaccines were more immunogenic, especially in subjects who were previously unprimed (preimmunization HAI antibody titer, < 5). In these subjects, the geometric mean titers of HAI antibody were significantly higher after vaccination with whole-virus vaccines than with split-product vaccines. Specific IgM antibody was found more frequently after vaccination with whole-virus vaccines (34%) than after split-product vaccines (11%).
(Am J Dis Child 1982;136:513-517)