[Antibody response of inactivated influenza vaccine in the elderly]

The antibody responses of 31 elderly persons (11 males and 20 females, mean 82.2 years) and 23 adults (mean 40.7 years) to inactivated influenza vaccine were studied. Participants were given twice the influenza vaccine containing A/Yamagata/32/89, A/Kitakyusyu/159/93, and B/ Mie/1/93. Serum specimens were obtained before vaccination, and 2 weeks and 3 months after the second vaccination. Antibody to influenza was determined by hemagglutination inhibition test (HI). The rates of fourfold or greater increases of HI antibody against the A/Yamagata, A/ Kitakyusyu, and B/Mie were 96.8%, 100%, and 74.2%, and there was no significant difference of the rates of fourfold or greater increases between elderly persons and adults. The rates of possession of HI antibody more than 128 in titer after vaccination were significantly higher than those of HI antibody before vaccination, and were maintained at high levels up to three months after the second vaccination. These results suggest that antibody response to the inactivated influenza vaccine is satisfactory in the elderly.