Efficacy of influenza vaccination in HIV-infected persons - A randomized, double-blind, placebo-controlled trial

Background: Although influenza vaccination is recommended in persons infect ed with HIV-1, its efficacy is unknown. Objective: To assess the immunogenicity, efficacy, and risks associated wit h influenza vaccination in persons infected with HIV-1. Design: Randomized, double-blind, placebo-controlled trial. Setting: Outpatient military clinic. Patients: 102 patients with HIV-1 infection. Intervention: Influenza vaccine (n = 55) or saline pla cebo (n = 47). Measurements: Influenza antibody titers, CD4(+) cell counts, and plasma HIV -1 RNA levels at baseline, 1 month after immunization, and 3 months after i mmunization; viral cultures from persons presenting with respiratory illnes s; and respiratory symptom interview. Results: Twenty-three placebo recipients (49%) and 16 vaccine recipients (2 9%) reported respiratory symptoms (P = 0.04). Ten placebo recipients but no vaccine recipients had laboratory-confirmed symptomatic influenza (P < 0.0 01) (protective efficacy, 100% [95% CI, 73% to 100%]). No effect on plasma HIV-1 RNA levels or CD4+ cell counts was noted. Conclusion: Influenza vaccination is highly effective in HIV-l-infected per sons and does not seem to be associated with substantial changes in viral l oad or CD4 cell count.