HIV-2 Infection: Where Are We Today?

Context: The choice of antiretroviral therapy for HIV-2 differs from that for HIV-1, underscoring the importance of differentiating between the two. Aims: The current study was planned to find out the prevalence of HIV-2 infection at our center and to find out the utility of the current diagnostic algorithm in identifying the type of HIV infection. Setting and Design: Retrospective analysis in a tertiary care teaching institute over a period of three years. Materials and Methods: All patients diagnosed as HIV infected using NACO/WHO HIV testing strategy III were included in the study. They were classified as HIV-1 infected, HIV-2 infected and HIV-1 and HIV-2 co-infected based on their test results. For discordant samples, immunoblotting result from National Reference Laboratory was considered as final. Statistical Analysis Used: Comparison between HIV-1, HIV-2 and HIV-1+2 positive groups for age, gender, route of transmission was made using chi squared test. P value < 0.05 was considered as significant. Results: Of the total of 66,708 patients tested, 5,238 (7.9%) were positive for HIV antibodies. 7.62%, 0.14%, 0.08% and 0.004% were HIV-1, HIV-2, HIV-1 and HIV-2 co-infected and HIV type indeterminate (HIV-1 Indeterminate, 2+) respectively. The current algorithm could not differentiate between the types of HIV infection (as HIV-1 or HIV-2) in 63 (1.2%) cases. Conclusion: In areas like the Indian subcontinent, where epidemic of both HIV-1 and HIV-2 infections are ongoing, it is important to modify the current diagnostic algorithms to diagnose and confirm HIV-2 infections.