The research, published in Proceedings of the National Academy of Sciences (PNAS), shows that ART is not only transforming outcomes for people living with HIV, but is also interrupting a process of natural selection on immune system genes (specifically variants of HLA-B) that could otherwise have reshaped human genetics over just a few decades.
Chimpanzees, the closest living relatives of humans, are believed to have experienced selective sweeps over two million years ago, that biased their immune gene repertoires towards variants that conferred protection against the progression of disease caused by viruses similar to HIV. This study highlights that the unchecked spread of HIV could have had a similar impact on humans, were it not for access to effective antiviral drug combination therapies.
Drawing on longitudinal data from antenatal cohorts in KwaZulu-Natal, South Africa - one of the regions most heavily affected by HIV - the team compared outcomes in the pre-ART era (1998–2005) with those in the modern treatment era (2015–2025).
Professor Philip Goulder, senior author from the Department of Paediatrics, said: “This study provides rare evidence of the scale of population genetic change that an infectious disease can drive over a relatively short timescale. What is remarkable is that modern medicine, through the rollout of antiretroviral therapy, has effectively interrupted this process of natural selection.”
Dr Bridget Penman, co-senior author from the Department of Biology at the University of Oxford, said: “HLA genes, which we study here, are some of the most diverse in the human genome. Our best explanation for this diversity is that they are subject to natural selection from co-evolving, rapidly changing, pathogens. However, most models of this process are conceptual. Here we have simulated changes in the frequencies of known HLA variants, in a specific population, driven by HIV.”
Read the full story on the Department of Paediatrics website.