The serologic response and late effects on viral load and CD4 count of influenza vaccination in HIV-infected patients with CD4 counts >200

Purpose: To assess the serologic response and the late virologie effects of influenza vaccination in HIV-infected patients. Methods: Randomized single-blind, placebo-controlled study of 32 asymptomatic HIV-infected patients with CD4 cell counts ≥ 200 cells/μL: 16 patients before and after vaccination with the recommended 1995-1996 trivalent influenza vaccine (FluV) and 16 patients vaccinated with saline placebo (P). Serum was tested for antibody (Ab) by hemagghitination inhibition. CD4 count was measured by flow cytometry and viral load (VL) was measured by the ultrasensitive branched-chain DNA assay sequentially up to 6 months post-immunization. Results: 75% of the patients who received FluV had a ≥ 4 fold rise in Ab to ≥ 1 antigens, 44% responded to all 3. None who received P responded. At 3-6 months post-vaccination the mean VL in the FluV group rose from a baseline of 71.9 KEq/ml (Range 0.49-285.3) to 87.2 KEq/ml (0.49-334.7) (NS) and declined from 32.4KEq/ml (Range 0.49-116) to 28.4 Keq/ml (0.49-113.7) in the P group (NS). None of the patients had a significant (≥ 0.5 log or 3 fold) increase in VL in the FluV group. The mean baseline CD4 count declined slightly from 653 to 627 in the FluV group (NS) and rose from 497 to 564 in the P group (NS). 50% in the FluV and 69% in the P group were on antiretrovirals. Conclusion: HIV-infected patients with CD4 counts >200 are able to mount an Ab response to influenza vaccination and do not experience any late (up to 6 months) adverse effects on VL or CD4 count.