Estimating historic and recent non-sexual HIV transmission to women in sub-Saharan Africa.

Introduction: The proportion of HIV infections in sub-Saharan Africa from non-sexual risks has been debated for decades. This article estimates that proportion for women. Methods: Use information from studies of discordant couples and from national surveys to estimate women's incidence from sexual transmission and average male-to-female sexual transmission. Compare those estimates to historic increases in women's infections and to recent incidence. Results: Based on four studies reporting incidence in women in discordant couples and on information from national surveys, annual HIV incidence in women from sexual transmission as a percent of women's prevalence as well as annual male-to-female transmission averaged across all infected men can both be (generously) estimated at 10%. In 10 of the 11 countries that reached at least 10% adult prevalence, percentages of pregnant women infected in sentinel surveys or estimated numbers of infected women by country increased at compound annual rates of 17-58% for multi-year periods during 1985-2000; if women's incidence from sexual transmission was 10% of women's prevalence, non-sexual transmission accounted for an estimated 41-83% of women's infections during those periods. Similarly, if 10% of men with unsuppressed viral loads sexually infect one woman per year, an estimated 65% of women's incident infections in 10 national surveys during 2019-25 were from non-sexual transmission. Discussion: According to evidence presented here, most HIV infections in women in sub-Saharan have been from blood-borne risks. Investigations of infections suspected from skin-piercing healthcare and cosmetic procedures can find and fix transmitting procedures and warn the public about blood-borne risks.