A meta-analysis, conducted by Keya Joshi and colleagues, reviewed empirical data to affirm or deny a decline in HIV incidence in sub-Saharan Africa that was suggested by Joint United Nations Programme on HIV/AIDS (UNAIDS) models. The study was published in the Journal of the International AIDS Society.
Authors stated that empirical data supported a reduced rate of new HIV infections in eastern and southern Africa. However, they cautioned that “recent incidence data are non-existent or very limited for many countries and key populations,” particularly in western and central Africa.
The investigators stratified data from prospective and cross-sectional studies that directly measured adult HIV incidence with blood samples according to population risk group, geographic location, sex, intervention arm, and calendar period.
A total of 291 studies including 22 sub-Saharan African countries were evaluated. The majority of studies were conducted in South Africa (n = 102), Uganda (n = 46), and Kenya (n = 41). The empirical analysis showed that, since 2010, average annual incidence in general population studies declined by 0.12/100 person-years (95% CI, 0.06–0.18; p = 0.001) among men and 0.10/100 person-years (95% CI, -0.02-0.22; p = 0.093) among women in eastern Africa. In southern Africa, incidence declined by 0.25/100 person-years (95% CI, 0.17–034; p = 0.0001) and by 0.42/100 person-years (95% CI, 0.23–0.62; p = 0.0002) among men and women, respectively. Additionally, in general population studies, the study observed that HIV incidence was generally higher in women with a median female-to-male incidence rate ratio of 1.47 (interquartile range [IQR] 1.11–1.83).
The report acknowledged that study design, testing algorithms, and definitions of incidence were highly variable across studies. Additionally, many countries and geographic locations had no published incidence data, which limited the ability to extrapolate findings to underrepresented locations.
The researchers concluded that empirical data generally supported the UNAIDS models that suggested declining HIV incidence trends through 2020. However, they noted several gaps in empirical data, and called for ongoing study of HIV incidence to assess the efficacy of control programs.