Time to peak serum antibody response to influenza vaccine in the elderly.

The earliest time at which serum antibody peaks following administration of influenza virus vaccine in elderly persons is not clearly defined. We compared the time intervals of 2 and 4 weeks after vaccination. A commercial trivalent vaccine containing the hemagglutinins of influenza viruses A/Texas/36/91(H1N1), A/Shangdong/9/93(H3N2), and B/Panama/45/90 was used. The hemagglutination inhibition antibody titers at 2 weeks after vaccination were identical to the hemagglutination inhibition antibody titers at 4 weeks for all three vaccine components.