Data from: Modelling the evolution of HIV-1 virulence in response to imperfect therapy and prophylaxis

Average HIV-1 virulence appears to have evolved in different directions in different host populations since antiretroviral therapy first became available, and models predict that HIV drugs can select for either higher or lower virulence, depending on how treatment is administered. However, HIV virulence evolution in response to 'leaky' therapy (treatment that imperfectly suppresses viral replication) and the use of preventive drugs (pre-exposure prophylaxis) has not been explored. Using adaptive dynamics, we show that increasing the uptake of imperfectly effective antiretroviral therapy can lead to the evolution of higher virulence, and that this evolution can erode some of the long-term clinical and epidemiological benefits of HIV treatment. The introduction of leaky pre-exposure prophylaxis can further amplify virulence evolution, but greatly reduces infection prevalence. Increasing the uptake of these imperfect interventions sometimes leads to counterintuitive increases in infection prevalence, but populations almost always fare better with access to interventions than without. However, untreated individuals could experience particularly poor clinical outcomes when virulence evolves. These findings predict that antiretroviral drugs may have underappreciated evolutionary consequences, but that maximizing drug efficacy can prevent this evolutionary response. We suggest that HIV virulence evolution should be closely monitored as access to interventions continues to improve.