Investigating zero transmission of HIV in the MSM population: a UK modelling case study

UNAIDS 90-90-90 goals for HIV have been surpassed in the UK, with focus now moving to ending transmission by 2030. The concept of zero transmission is complex and many factors can influence transmission. We aimed to investigate how the target of zero transmission might be reached in the UK.

We developed a de novo Markov state transition open cohort model of HIV with a 50-year time horizon, which models six key screening, treatment and prevention parameters, including treatment-as-prevention (TasP) and pre-exposure prophylaxis (PrEP). We studied the anticipated HIV epidemic trajectory over time in men who have sex with men (MSM), with and without changing the six key parameters, defining zero transmission as a 60% reduction in incidence compared with 2010 incidence.

Zero transmission in the MSM population was not achieved within the model's time horizon in our base case scenario, when the six key parameters were set to their 2019 values. Several future scenarios were explored, including a combination approach to preventing HIV transmission through increasing five key parameter values and considering three different TasP values; zero transmission was achieved by 2030 in the scenario where TasP was increased from its current level of 97-99%, avoiding 48,969 new HIV cases over the time horizon and reducing the lifetime risk of acquiring HIV for HIV-negative MSM not using PrEP from 13.65 to 7.53%.

Zero transmission in the UK MSM population can be reached by the target year of 2030 with bold changes to HIV policy. A combination approach such as the UK Government's 'Towards Zero' Action plan, impacting multiple policies and including an increase in TasP, has the potential to achieve meaningful reductions in HIV transmission and meet this ambitious goal.