Influenza vaccination of human immunodeficiency virus-infected adults. impact on CD4 cell count and plasma viral load

BACKGROUND: The aim of this study was to assess the effect of Influenza vac cination on plasma HIV viral load and CD4 T-lymphocytes in patients with ad vanced HIV disease. PATIENTS AND METHOD: Observational study carried out in HIV-infected patien ts with a CD4 cell count < 200 x 10(6)/l on highly active antiretroviral th erapy (HAART). Influenza vaccine was voluntarily offered and plasma viral l oad and CD4 cell counts were measured at baseline, 4 weeks and 12 weeks in vaccinated and control subjects. RESULTS: Sixteen patients were analysed, 10 of them being immunized with th e Influenza vaccine. A significant decline in CD4 cell counts at 4 and 12 w eeks and an increasing trend of vital load were seen in all immunized patie nts who had a high viral load at the time of vaccination (n = 6), but not i n those with an undetectable viral load. The mean decrease of CD4 T-lymphoc ytes; in these 6 patients was 49.8%. Three patients showed a huge drop of t he CD4 cell count (over 60% of baseline). CONCLUSIONS: Influenza vaccination at severely immunocompromised HIV-infect ed patients who are failing to HAART might be associated with an immunologi cal impairment.