Cardiopulmonary hospitalizations during influenza season in adults and adolescents with advanced HIV infection.

The etiologic role of influenza in hospitalizations and deaths among persons infected with HIV since the introduction of highly active antiretroviral therapy (HAART) is not known. A retrospective cohort study was performed of all persons aged 15 to 50 years with AIDS or advanced HIV infection enrolled in the Tennessee Medicaid program from 1995 through 1999, representing 7368 person-years of follow-up. The influenza season was defined based on local virus surveillance, and hospitalizations were measured for acute cardiopulmonary causes and deaths from any cause throughout the year. From 1995 through 1999, cardiopulmonary hospitalization rates in HIV-infected patients declined by 53% and death rates declined by 77%. The influenza-attributable hospitalization rate was 48 (95% confidence interval [CI]: 16-91) per 1000 persons in 1995 and 5 (95% CI: -0.5-11) per 1000 persons per year during 1996 through 1999, after the introduction of HAART. Influenza-associated hospitalizations have declined in patients with HIV infection in the post-HAART era. Rates remain comparable to rates in other high-risk groups for which annual influenza vaccination is recommended, however.