Antibody response after influenza vaccination in HIV-infected individuals: a consecutive 3-year study

In a consecutive 3-year study the antibody response after immunization with influenza vaccine of a cohort of HIV-infected adults was studied. The haemagglutination-inhibiting (HAI) antibody titres after vaccination correlated with the number of CD4(+) T lymphocytes (p<0.001), the prevaccination antibody titres (p<0.001), and the proliferative response to anti-CD3 (p<0.001). Severely impaired antibody responses were observed in HIV-infected individuals with CD4(+) T-lymphocyte counts < or =100x10(6)/l. Significantly higher prevaccination antibody titres were observed in healthy controls in the 2nd or 3rd year of vaccination, but not in HIV-infected individuals. Annually repeated vaccination of HIV-infected individuals did not lead to higher postvaccination antibody titres. Annual vaccination of HIV-infected individuals with CD4(+) T-lymphocyte counts exceeding 100x10(6)/l seems to be worthwhile, although it may not be expected to render the same level of protection against influenza as in non-infected individuals.