A systematic review of heterosexual anal intercourse and its role in the transmission of HIV and other sexually transmitted infections in Papua New Guinea

BACKGROUND Papua New Guinea (PNG) has a high burden of sexually transmitted infections (STIs) and the highest adult HIV prevalence in the Pacific region. Despite this burden of disease, heterosexual anal intercourse (HAI) has rarely been considered. Given the increasing number of, and interest in, behavioural surveys in PNG and the changing nature of PNG's HIV epidemic, it is timely to conduct a systematic review of HAI in PNG order to improve sexual health. METHODS We performed a systematic review of HAI in PNG as reported in peer-reviewed and non-peer-reviewed publications for the period 1950-May 2012. The search strategy identified 475 publications. After screening by geographical location, topic and methodology, we identified 23 publications for full text review, following which 13 publications were included in the final review. Using data from the review, we performed a risk equation analysis to demonstrate the potential impact of HAI on HIV acquisition and incidence in PNG. RESULTS There is a paucity of well-informed behavioural research on HAI in PNG. Inconsistency in key questions on HAI made it impossible to conduct a meta-analysis. The data available on HAI shows that it is practiced in all geographical areas and among all populations. Of those who reported HAI, rates varied from as low as 8% to as high as 77% depending on the recall period and partner type. Condom use during HAI was consistently low. Our risk equation analysis indicates that even if only 20% of females engage in HAI, and only 10% of sex acts involve HAI, the total number of new HIV infections among females would be 40% greater than if vaginal intercourse only occurred. CONCLUSIONS Our findings of indicate that HAI may be an important driver of the HIV epidemic in PNG. In order to improve the sexual health of Papua New Guineans, efforts are required to improve behavioural surveillance of HAI as well as develop national HIV/STI programing and policy to better address the risks associated with unprotected HAI.