The incidence of HIV-2 infection in Spain is declining - a registry data analysis

HIV-2 infection is a neglected disease caused by a human retrovirus that causes AIDS more slowly than HIV-1. Infection with HIV-2 is endemic in West Africa. Given its differential features, guidelines recommend ruling out HIV-2 infection in all newly diagnosed HIV-seropositive individuals.

A national registry of HIV-2 cases was created in Spain in 1989, following the first report of three HIV-2+ individuals in Barcelona. The main demographics, clinical, and virological data are reported up to December 2023.

A total of 424 individuals with HIV-2 infection were recorded in the Spanish registry. After a peak in 2009 when 31 cases were reported, new HIV-2 diagnoses steadily decreased. Less than 10 cases/year have been notified since the COVID-19 pandemic. In 2023, only eight cases were reported. Mean age at HIV-2 diagnosis was 44 years old, ranging from birth to 83 years. A total of 265 (62.5%) were male. Migrants predominated, being 322 (76%) Sub-Saharan Africans; however, 60 (14.2%) were native Spaniards. Heterosexual exposure was the most likely route of infection in at least 287 (67.7%) cases. A few cases could be traced to transfusions (n = 4), vertical infection (n = 2), or injection drug use (n = 7). In addition, 15 individuals (3.5%) were men who had sex with men. Coinfection with HIV-1 was recognized in 39 (9.2%) individuals. Molecular characterization of HIV-2 subtypes was performed in 139 individuals, 121 being infected with subtype A and 18 with subtype B.

The annual incidence of HIV-2 infection in Spain has decreased after peaking 15 years ago, being the current number of cases below 10 per year. Three-quarters are African migrants, and two-thirds are male. Circulation of HIV-2 in Spain is limited and steadily decreasing.