Effect of Influenza Vaccination on Disease Progression Among HIV-infected Persons

Objective: To describe the effect of influenza vaccination on long-term change in CD4 count and HIV RNA level, and on progression to AIDS or death.

Design And Setting: A longitudinal medical record review set in 113 medical clinics in 10 United States cities.

Patients: A total of 36,050 HIV-infected persons aged > or = 13 years in care for HIV infection.

Main Outcome Measures: Change in CD4 count and HIV RNA level at follow-up (3-12 months after vaccination); hazard ratios (HR) for association of influenza vaccine with progression from baseline CD4 or HIV RNA level to AIDS and to death.

Results: The median CD4 count among all persons decreased 28 cells/year during follow-up, with no difference in change in CD4 count between the 8007 (40%) vaccinated (median = 6 months, vaccine to follow-up CD4 count) and the 11,794 unvaccinated persons. In a viral load subanalysis, median HIV RNA level decreased 90 copies/ml per year among all persons during follow-up; decreases were not different between vaccinated and unvaccinated persons (median = 7 months, vaccine to follow-up HIV RNA level determination). Influenza vaccination was weakly associated with decreased risk of progression to clinical AIDS [HR 0.93; 95% confidence interval (CI), 0.87-0.99], but not associated with time to death (HR, 0.97; CI, 0.93-1.01).

Conclusions: No negative long-term effect of influenza vaccination on CD4 counts, HIV RNA levels, or progression to AIDS or death was found in this HIV-infected population. These data suggest that physicians should not withhold influenza vaccine because of concerns about long-term detrimental effects of increased viral replication.