Trends in HIV-2 Seroprevalence at the National Reference Center of HIV from 2005 to 2014 in Lome, Togo

Background: In Togo, the HIV/AIDS epidemic is characterized by the circulation of the 2 subtypes of HIV. Thus, patients infected with HIV-2 are diagnosed and monitored in the care centers. Objective: To document the trend of HIV-2 prevalence over a decade of activities of the National Reference Center for HIV tests and screening (CNR-VIH). Methods: A cross sectional study was carried out from the screening data archived from January 2005 to December 2014 at the CNR-VIH, a laboratory located in the Sylvanus Olympio University Hospital (CHU SO) Lome. The sampling consisted of adults and children outpatients or those who were hospitalized in CHU SO, subjects presenting for voluntary testing, pregnant women and patients or samples referred for HIV confirmation. All samples were tested for HIV-1 and HIV-2 infections by combining ELISA and rapid diagnostic tests. Result: During the decade, 34,077 subjects were screened for HIV infection. The overall prevalence of HIV infection was 20.70% (7055/34077). In 10 years, the prevalence of HIV infection in CNR-VIH decreased significantly from 35.40% CI95% [34.50% - 36.20%] in 2005 to 14.20% CI95% [13.60% - 14.70%] in 2014 (p = 0.03). The prevalence of HIV-1, HIV-2 and dual HIV1&HIV-2 was respectively 20.40%, 0.23% and 0.07%, with annual prevalence of HIV-2 between 0.07% and 0.39%. The differences between the HIV-2 prevalence over the decade were not statistically significant (p > 0.15). A 4-year-old child from mother-to-child HIV-2 transmission was diagnosed. Sixty-five percent of adult patients were over 40 years of age with an average age of 43.5 ± 11.3 years. Conclusion: Data from the National Reference Center for HIV Tests in Togo over the last ten years confirm the existence of a weak epidemic of HIV- 2 infection with a tendency towards stability.