Male circumcision rates in 1950 were negatively correlated with HIV-2 prevalence from 1985 to 1991 in West Africa, according to data from a study recently published in PLoS One.
“HIV-2 has been less studied than HIV-1, but is nevertheless a considerable threat to public health, since it has spread worldwide and is probably infecting more than one million people,” João Dinis Sousa, of the department of microbiology and immunology at the University of Leuven, Belgium, and colleagues wrote. “Evidence for the protective role of male circumcision at the population level has only been published for HIV-1. The scarcity of HIV-2 prevalence data limits the possibilities of testing the association between male circumcision and HIV-2 prevalence. Most UNAIDS reports publish joint HIV prevalence without specifying virus type.”
The researchers analyzed serosurveys regarding HIV-2 for 30 cities in West Africa and used Bayesian methods to form prevalence estimates. They used ethnographic literature and fieldwork to estimate historic circumcision rates for 218 ethnic groups in the region, then generated 1,000 sets of historic circumcision rates per city, analyzing the correlation between circumcision and HIV-2 prevalence.
Sousa and colleagues reported that male circumcision was significantly less common and more geographically varied from 1890 to 1920 than the present day, practiced by a minority or not practiced at all among 72 (33%) ethnic groups. Regions with higher rates of circumcision in 1950 had lower HIV-2 prevalence when serosurveys first began in the 1980s, the researchers reported (Spearman rho = -0.546, interquartile ratio: –0.553 to –0.546; P ≤ .0021). The correlations were still significant in all tests performed using 20 or more cities (P ≤ .013). Circumcision rates were lower in 1950 in the cities of Guinea-Bissau and Cote d’Ivoire, both of which researchers believed to be the earliest epicenters of HIV-2.
A press release accompanying the study noted that while the study was limited by the fact that HIV-2 prevalence and circumcision data were obtained in different years, the authors said HIV-2 appeared to have high prevalence only in cities with lower circumcision rates.
“Lack of circumcision may have been a driving factor in initial HIV-2 emergence,” Sousa said in the press release. – by Andy Polhamus
Disclosure: The researchers report no relevant financial disclosures.