Study Objective: To ascertain whether subjects infected with human immunodeficiency virus (HIV) generally develop protective hemagglutination inhibition antibody responses to inactivated influenza vaccines.
Design: Prospective study of 104 persons before and after immunization.
Setting: Outpatient clinic and hospital ward.
Patients: Persons with the acquired immunodeficiency syndrome (AIDS) (n = 25), AIDS-related complex (n = 14), and HIV-seropositive men with only lymphadenopathy or no symptoms (n = 27). Controls were HIV-seronegative homosexual men (n = 22) and HIV-seronegative heterosexuals (n = 16).
Interventions: Subjects were immunized with inactivated vaccines containing 15 μg of each of the following influenza virus hemagglutinins: A/Taiwan/1/86 (HINI), A/Mississippi/1/85(H3N2), A/Chile/1/83 (HINI), and B/Ann Arbor/1/86.
Measurements and Main Results: Fourfold or greater antibody responses occurred less frequently in subjects with HIV infections than in HIV-seronegative controls. Protective levels (1:64 or greater) of hemagglutination inhibition antibodies were attained by 94% to 100% of HIV-seronegative controls, 52% to 89% of HIV-seropositive asymptomatic subjects, and 13% to 50% of subjects with AIDS or AIDS-related complex. No increase in the prevalence or level of serum HIV p24 antigen or clinical deterioration was detected among HIV-infected persons after influenza immunization.
Conclusions: Because of the poor antibody responses to influenza vaccines among HIV-infected subjects, even in many with no or minimal symptoms, alternative strategies for preventing influenza, such as booster doses of influenza vaccine, prophylaxis with amantidine, or both should be considered.