Akullian, A., Bershteyn, A., Klein, D., et al. AIDS (May 2017), 31: 1755–1764, doi: 10.1097/QAD.0000000000001553
This modeling study estimated HIV incidence among male/female age pairings to identify high-risk age groups and high-risk age pairings for HIV transmission. The authors analyzed data from a longitudinal surveillance system (2004–2015) in KwaZulu-Natal, South Africa, that included 10,260 women and 7,839 men. New HIV infections were documented in 1,788 women and 579 men. The highest incidence occurred among women aged 15–24 years who reported a male partner aged 30–34 years, followed by women of the same age group with a partner aged 25–29 years and women between ages 25 and 49 with a male partner aged 25–29. Men aged 25–30 years with a female partner of the same age group experienced the highest risk of HIV transmission. Women with a male partner under age 35 had three times greater risk of acquiring HIV than those with partners ≥35 years. Men with a female partner aged 25–34 experienced higher risk than those with partners aged 15–19. HIV acquisition risk may be driven more by exposure to a partner in a high-risk age group than by age gaps, and is determined by a sexual partner’s profile (including age), as well as community-level determinants, including viral load, antiretroviral treatment coverage, and risky sexual behaviors. Prevention interventions should focus on those most at risk of both acquiring and transmitting HIV.