Responses of elderly subjects to a new subunit influenza virus vaccine.

The serologic responses and the side effects resulting from the administration of a new subunit vaccine against influenza were compared with those of a currently available whole-virus vaccine in an elderly population. The subunit vaccine is prepared by cleavage of the hemagglutinin and neuraminidase surface antigens from the virus with a cationic detergent, cetyltrimethylammonium bromide. The resulting vaccine is more selectively reduced to these primary antigens than are the available subunit vaccines produced by the use of lipid solvents that disrupt the viral membrane [1]. Previous studies in younger individuals with new subunit preparations of earlier H3N2-subtype viruses as well as influenza A/New Jersey/76 (HswN1) and B/Hong Kong/73 viruses indicated that antibody responses in primed, although not in unprimed, populations wee comparable to those induced by whole-virus vaccines and that side effects were few [2,3]. There were not statistically significant differences in the serologic responses of the vaccine recipients except that the percentage of recipients who achieved titers of HAI antibodies of 1:10 or 1:20 to influenza B/Singapore/222/70 virus after vaccination was greater in the subjects who received the subunit vaccine. There were no statistically significant differences in the percentage of recipients with an antibody response (fourfold or greater in titer) or in the geometric mean titers of HAI antibodies after vaccination between those who had received the trivalent influenza virus vaccine in 1979 and those who had no history of vaccination in 1979. Mild redness and/or tenderness were noticed at the injection site between 6 and 48 hr after vaccination in 16 subjects who received the subunit vaccine and in four subjects who received the subunit vaccine and two who received the whole-virus vaccine (P less than 0.01 by chi 2 test). One patient in each group complained of headache; four subjects who received the subunit vaccine and two who received the whole-virus vaccine complained of fatigue.