Increased survival among HIV-1 and HIV-2 dual-infected individuals compared to HIV-1 single-infected individuals.

OBJECTIVE: To compare survival times of HIV-1 single and HIV-1 and HIV-2 dual-infected individuals. DESIGN: Prospective open cohort study. METHODS: We analysed data from 259 HIV-1-seroincident cases (either HIV-1 single or HIV-1 and HIV-2 dual-infected) from a cohort with long follow-up (~20 years) in order to study the influence of type of infection and infection order on mortality. Sex and age at HIV-1 infection date was controlled for in a Cox proportional-hazards model. RESULTS: Dual-infected individuals had a 42% longer time from HIV-1 infection to death compared with single-infected individuals, adjusting for age asymmetries between groups. Dual-infected individuals with an HIV-2 infection preceding the HIV-1 infection had a more than two-fold lower mortality risk during follow-up than HIV-1 single-infected individuals. CONCLUSION: Survival time is longer and the risk of progression to death is lower among HIV-1 and HIV-2 dual-infected individuals compared to HIV-1 single-infected individuals. This natural inhibition could have implications for the development of future HIV-1 vaccines and therapeutics.