Immunization of elderly volunteers with the 1988?89 inactivated whole influenza vaccine: Assessment of antibody responses by haemagglutination inhibition and single radial haemolysis tests

Abstract

The immunogenicity of inactivated whole trivalent influenza vaccines (A/Taiwan/1/86 (H1N1), A/Sichuan/2/87 (H3N2), and B ijing/1/87) recommended for the 1988-89 winter season was evaluated in 236 elderly (mean age 71 years) high risk volunteers. An overall significant increase in the number of subjects with protective haemagglutination inhibiting (HI) antibodies (titer > 1:40) against vaccine components was observed after vaccination. Nevertheless, a percentage of individuals (ranging from 56% to 62%) remained without protective antibodies and the number of people showing a positive response was limited (from 32% to 41%). By the comparative analysis of the results obtained examining the presence of protective levels of antibody in the sera from 91 volunteers using HI versus the single radial haemolysis (SRH) test, we obtained evidence for a higher sensitivity of SRH technique especially against B antigen.

Guidelines for the management of adult lower respiratory tract infections

“…In the elderly, the response is not as good. Between 30-70% reach an HI titre of .1:40 [260][261][262][263]. In these age groups, a double dose, or a booster dose, has been shown to increase the geometric mean IgG antibody concentration by ,15% [264].…”