The first trial in Africa of two combination vaccines to prevent HIV has been halted after researchers concluded it was not working.

The vaccines (part of the PrEPVacc study) were being tested on 1,500 people aged between 18 and 40 in Uganda, Tanzania and South Africa.

The African-led trial, which began in December 2020, was stopped last month after an interim review of progress. The final results are expected to be made public in late 2024.

The trial of a pre-exposure prophylaxis pill running alongside the vaccines tests will continue.

Dr Eugene Ruzagira, trial director from the Uganda Virus Research Institute (UVRI) and assistant professor of epidemiology at the London School of Hygiene & Tropical Medicine, said: “Vaccinations to PrEPVacc trial participants have been stopped because an analysis of the data collected so far by our independent data-monitoring committee has led them to conclude that there is little or no chance of demonstrating that the vaccines we are testing are reducing the risk of acquiring HIV.”