Influenza vaccination of human immunodeficiency virus (HIV)-infected adults: impact on plasma levels of HIV type 1 RNA and determinants of antibody response.

We assessed the effect of influenza vaccination on plasma levels of human immunodeficiency virus type 1 (HIV-1) RNA and the impact of age, plasma HIV-1 RNA level, CD4 cell count, and anti-HIV therapy on immune response. Forty-nine adults (mean age, 38.7 years; mean CD4 cell count +/- SD, 190 +/- 169/mL; mean plasma HIV-1 RNA level +/- SD, 154,616 +/- 317,192 copies/mL) were immunized. Elevations of > or = 0.48 log in plasma HIV-1 RNA levels occurred in two (4%) of 49 subjects within 4 weeks of vaccination. A fourfold or greater increase in antibody titer occurred in 13 (45%) of 29 subjects, correlating directly with CD4 cell count (P = .002) and inversely with plasma HIV-1 RNA level (P = .034). By multivariate analysis, CD4 cell count was a stronger predictor of antibody response than was plasma HIV-1 RNA level. We conclude that increases in plasma HIV-1 RNA levels following influenza vaccination are rare and transient and that antibody response is impaired with CD4 cell counts of < 100/mL and plasma HIV-1 RNA levels of > 100,000 copies/mL. Prospective trials are needed to evaluate the impact of highly active therapy on immune response after vaccination.