More than half a million people in sub-Saharan Africa could die between now and next year from Aids-related illnesses amid the Covid-19 pandemic – unless governments move to address the issue.

A modelling analysis done by the World Health Organization (WHO) and UNAids shows that the impact of a six-month disruption of antiretroviral (ARV) therapy could effectively set the clock back on Aids-related deaths to 2008, when there were more than 950,000 deaths on the continent.

“The terrible prospect of half a million more people in Africa dying of Aids-related illnesses is like stepping back into history,” Tedros Adhanom Ghebreyesus, the WHO director-general, said in a statement.

UNAids executive director Winnie Byanyima warned that treatment could be interrupted, with HIV services closed or unable to supply ARV therapy because of a breakdown in the supply chain.

“It could even be because services simply become overwhelmed due to competing needs to support the Covid-19 response,” Ms Byanyima said.

“There is a risk that the hard-earned gains of the Aids response will be sacrificed to the fight against Covid-19, but the right to health means that no one disease should be fought at the expense of the other.”

The WHO head said that countries needed to ensure that those diagnosed with HIV were adhering to treatment and that testing services would not be disrupted.

Some countries are already taking important steps, for example ensuring that people can collect bulk packs of treatment and other essential commodities, including self-testing kits, from drop-off points, which relieves pressure on health services and the health workforce.

“It will be important for countries to prioritise shoring up supply chains and ensuring that people already on treatment are able to stay on treatment,” Dr Tedros added.