Influenza A among patients with human immunodeficiency virus: An outbreak of infection at a residential facility in New York City

Although annual influenza vaccination is recommended for persons who are in fected with human immunodeficiency virus (HIV), data are limited regarding the epidemiology of influenza or the effectiveness of influenza vaccination in this population. We investigated a 1996 outbreak of infection with infl uenza A at a residential facility for persons with AIDS. We interviewed 118 residents and employees, reviewed 65 resident medical records, and collect ed serum samples for measurement of influenza antibody titers. After contro lling for history of smoking, influenza vaccination, and resident or employ ee status, in a multivariate model, HIV infection was not statistically ass ociated with influenza-like illness (ILI). Symptoms and duration of ILI wer e similar for most HIV-infected and HIV-uninfected persons. However, 8 (21. 1%) of 38 HIV-infected persons with ILI (vs. none of 15 HIV-uninfected pers ons) were either hospitalized, evaluated in an emergency room, or had ILI l asting greater than or equal to 14 days (P = .06). Vaccination effectivenes s (VE) was similar for HIV-infected and HIV-uninfected persons. Vaccination was most effective among HIV-infected persons with CD4 cell counts of >100 cells/muL (VE, 65%; 95% CI, 36%-81%) or HIV type 1 virus load of <30,000 c opies/mL (VE, 52%; 95% CI, 11%-75%). Providers should continue to offer inf luenza vaccination to HIV-infected persons.