Testing everyone in a community for HIV and offering immediate treatment to all those who test positive can cut the number of new infections by around a third, according to new research.

The study took place in Zambia and South Africa, both countries with a high burden of disease, and researchers believe that this approach could go some way to ending the HIV epidemic in these two countries and elsewhere.

In 2017, around 37 million people were living with HIV worldwide and there were 1.8 million new infections. Countries in southern Africa account for a large proportion of this number, with around 48,000 new infections in Zambia and 290,000 in South Africa.

Although HIV incidence is declining, the world is unlikely to reach the UNAIDS target of less than 500,000 new infections a year by 2020 so new approaches to tackling the epidemic are needed.

The trial, led by researchers at the London School of Hygiene and Tropical Medicine (LSHTM) and Imperial College, London, involved 21 communities of around 50,000 people each.

Participants were divided into three study arms. The first arm received annual door-to-door voluntary HIV testing and those that tested positive received immediate treatment.