Even before the Trump government slashed its overseas HIV budget last year, with prevention facing some of the deepest cuts, very few countries in the world had enough people using PrEP to substantially reduce their HIV infection rate, or even to make a noticeable dent in it.
Dr Andrew Hill of Liverpool University in the UK told the Conference on Retroviruses and Opportunistic Infections (CROI 2026) in Denver that cutting the US’s PEPFAR PrEP programme had made the situation considerably worse. In some African countries the number of people on PrEP has fallen by as much as 98%. If this trend continued, Hill said, far from HIV infections falling to UNAIDS’ target of no more than 370,000 a year, there would continue to be 1.4 million infections a year – or perhaps even more.
PrEP needs to be given to large numbers of people to have a significant effect on the HIV epidemic, Hill said. It should also be cheap enough to enable mass distribution and to be targeted to the people at most risk. Instead of this, it was currently becoming harder to access and more expensive.
This is because one of the more awkward aspects of HIV prevention, as opposed to treatment, is that most people who use a prevention method – whether that be a condom, a pill or an injection – would not have caught the virus anyway if they hadn’t used it. Over time, the protective efficacy of a regularly used prevention method builds up, because years of failing to use it make an infection more likely. Alternatively, if one use of the method ensures a long period of protection – as in a long-lasting vaccine – then that prevents a lifetime high probability, even a likelihood, of infection.
But we don’t have a long-lasting vaccine, so even a 100% efficacious PrEP method has to reach a lot of people to prevent one HIV infection, Hill said. In this respect we have a rough guess at how many people might have to be given PrEP to prevent one infection from the PURPOSE randomised trials of lenacapavir. In PURPOSE 1 in African cisgender women, and PURPOSE 2 in gay and bisexual men and trans people worldwide, six-monthly injections of lenacapavir PrEP were almost 100% effective.
Furthermore, both studies estimated the background HIV incidence in their target population by measuring the rates of recent infection in people who came forward for the study, not knowing they had HIV. These happened to be the same: in PURPOSE 1 and PURPOSE 2 the background incidences were 2.41% and 2.37% respectively, meaning that one HIV infection was prevented for every 42 people who would otherwise have acquired HIV over the course of a year.
How many countries are achieving this rate of PrEP coverage in their at-risk populations? Even before 2025, very few.
Hill compared the numbers of people on PrEP with their HIV incidence to the end of 2024. Currently, the only countries delivering PrEP to more than 42 people per new HIV acquisition annually are Australia, Denmark and Norway, with the UK just under the wire at 40 PrEP users per new HIV infection. (In the UK, there were 110,000 people on PrEP and 3043 new infections last year; in Australia there were 48,000 people on PrEP and 757 infections.)
Even the US, with 591,000 PrEP users and 31,800 new infections in 2025, only gives PrEP to 15 people per new infection.
While some African countries had achieved large numbers of people on PrEP by the end of 2024 – 860,000 in South Africa and 420,000 in Zambia – these countries have high HIV acquisition rates. There was only one person on PrEP for five infection in South Africa or for 14 in Zambia.
And that was before the PEPFAR cuts. There are now 28% fewer PrEP users in South Africa (where PrEP receives substantial government funding) and 58% fewer in Zambia. Some countries have done worse. In Uganda, the number of people on PrEP has fallen by 70%, in Malawi by 75%, and in Nigeria by a staggering 98%, from 390,000 in 2024 to just 7,000 in 2025. In Uganda and Nigeria, this now means more infections per year than people on PrEP – in the case of Nigeria, 10 infections for every person on PrEP.
Even some countries receiving no PEPFAR funding saw PrEP coverage fall in 2025. Brazil had an estimated 170,000 people on PrEP at the end of 2024 and 101,000 a year later, meaning two people on PrEP per new HIV acquisition. Others have still hardly got off the ground – India, the world’s most populous country, currently has 2100 people on PrEP, or two for every 100 HIV acquisitions.
Modelling shows that at these rates of PrEP coverage, global HIV infections in 2030 will number 1.45 million – exactly what they were in 2022.
How can we redress this situation? We could restrict PrEP coverage to those at the very highest risk, higher than the 2.4% a year seen in PURPOSE, thus ensuring more infections stopped per dollar. There are such populations, such as sex workers in some African countries, where annual HIV incidence ranges from 4.6% in South Africa to as high as 9% in Ethiopia and Tanzania. But populations with this kind of incidence are small, and restricting PrEP to a specialist intervention for a few people goes against the global push for wider provision.
Making PrEP as cheap as possible has allowed wider provision, and generic tenofovir disoproxil/emtricitabine is currently available for about US $35 per person a year. But injectable formulations have a much higher price tag.
ViiV Healthcare have signed an agreement to license 90 countries to distribute generic long-acting cabotegravir for $180 a year, and Gilead Sciences have signed with 120 countries to distribute it at $120 a year. But this leaves between 75 and 105 countries to negotiate prices that will lie somewhere between these and the US list (maximum) prices of $22,100 and $28,218, respectively. This is despite Andrew Hill finding last year that lenacapavir could be manufactured for the same price as oral PrEP – $35 to $46 a year – and still make a profit, or even less if it scales up to millions of users. Perhaps because of cost, but also because they require a medical setting, currently only 2.9% of the 2.2 million people on PrEP worldwide are taking cabotegravir, and 0.9% lenacapavir. And that 2.2 million represents only one-tenth of the UNAIDS target.
“PrEP is having little or no impact on HIV incidence in low- or middle-income countries,” Hill said.
In the face of this bleak picture, what does he recommend?
“We have achieved high coverage of ART worldwide: now we need to do the same for PrEP,” he said. “We should devise an HIV Protection Fund of $500 million a year to get the first 10 million people on lenacapavir in low and middle-income countries.”
