The rise and fall of HIV in Kinshasa over a century.

Kinshasa was the crucible of the HIV pandemic, the only place on Earth where its path can be tracked over a century through history, demography, evolutionary biology, epidemiological studies, and population-based surveys. Altogether, these tools demonstrate that HIV is fading away from Kinshasa. Between HIV's arrival (≈1916) and the last survey (2023-2024), Kinshasa's population increased from 14 000 to 17 million inhabitants. After an exponential growth of persons with HIV (PWH) from the mid-1950s until 1988, this stalled between 1988 and 2013-2014. From 85 900 PWH in 2013-2014, this number dropped to 35 500 in 2023-2024, while population increased by 6 million. After culminating at ≈4.8% (1988), prevalence in persons aged 15-49 years now stands at 0.4% (2023-2024). While 35% of sex workers were infected in 1988, this proportion decreased to 12% in 2002, 10% in 2012 and only 5% in 2018-2019. Safer sex, antiretrovirals, and internal migrations from lower-prevalence rural regions contributed to HIV's decline, an evolution facilitated by a long-standing and almost universal practice of circumcision. Alterations in sex work patterns may have been pivotal: economic hardship and risk awareness stifled demand, fewer clients and higher condom use attenuated the risk for sex workers which in turn protected their subsequent clients. A virtuous cycle might have taken hold. Genetic factors enhancing biological susceptibility to HIV could have rarefied through a combination of mechanisms. This unrelenting downward trend over four decades suggests that the 'elimination' of HIV, at least in certain areas, is feasible.