The global response to HIV has suffered its sharpest financial reversal in more than two decades, with donor government funding plunging 25% in 2025 just as scientific breakthroughs have brought the prospect of ending AIDS closer than ever.
The unprecedented decline -- driven entirely by a steep reduction in United States disbursements -- is threatening prevention, testing, treatment and community-led programs across low- and middle-income countries, global health leaders warned on Monday at the opening of the 26th International AIDS Conference in Rio de Janeiro.
Donor government support fell by $2.1 billion, from $8.3 billion in 2024 to $6.2 billion in 2025, marking the largest single-year fall since international HIV financing began scaling up in 2002. Funding has now dropped to its lowest level since 2007, according to a joint analysis by UNAIDS and the health policy organisation KFF.
The decline exposes the vulnerability of a global HIV response heavily dependent on Washington. The United States provided 74% of all donor government financing for HIV in 2025, even after reducing its support, while funding from all other donor governments combined has halved since 2011.
The reports were released as nearly 7,000 scientists, policymakers, healthcare providers, donors and people living with or affected by HIV gathered in Brazil for AIDS 2026, the world’s largest conference on HIV science and policy.
Opening the conference, International AIDS Society President and AIDS 2026 International Co-Chair Dr Beatriz Grinsztejn described the crisis as a defining test for the global response.
“We come to Rio de Janeiro at a moment of real danger for the HIV response,” she said.
Grinsztejn warned that donor support had never fallen “so far, so fast,” with the consequences already being felt by vulnerable communities and countries struggling under heavy debt burdens.
The collapse in financing comes despite extraordinary advances in HIV medicine, including long-acting prevention technologies capable of protecting people for months with a single dose.
Yet global health leaders warned that scientific progress will have little impact if countries cannot afford to provide the medicines, testing and community services needed to deliver them.
The contradiction lies at the heart of AIDS 2026: the tools required to control the epidemic increasingly exist, but the financial and political commitment needed to make them universally available is weakening.
The consequences are already visible.
An estimated 1.2 million people acquired HIV in 2025, while 570,000 died from AIDS-related illnesses. Although both figures represent major reductions from 2010, nearly nine million people living with HIV remain without treatment, and the world is not on course to end AIDS as a public health threat by 2030.
HIV testing fell by 22% in high-burden settings between 2024 and 2025, while access to pre-exposure prophylaxis, or PrEP, declined by 38% across 62 reporting countries. In some settings, funding for condoms fell by more than 90%, according to UNAIDS.
Domestic HIV financing rose by 4% in 2025 and now represents nearly 60% of total global resources, while more than 55 countries have committed to further increases in 2026.
However, the reports warn that domestic investment cannot replace international support at the speed or scale required, especially in low- and middle-income countries where donor funding sustains laboratories, medicines, community outreach, prevention and treatment programmes.
Total resources available for HIV from all sources stood at an estimated $17.6 billion in 2025, an 18% decline from the previous year.
UNAIDS Executive Director Winnie Byanyima said countries must prepare for a fundamental transformation in how their HIV programs are financed.
“The era of relying on international aid is over,” she said.
She called for greater domestic spending but said heavily indebted countries would need debt restructuring and broader reform of the international financial system to free resources for health, education and development.
Conference leaders warned, however, that national responsibility must not become an excuse for wealthy governments to abandon global cooperation.
South African Deputy Health Minister Mathume Joseph Phaahla said African governments must increase their investments but could not replace decades of international partnership on their own.
No country, he argued, can independently reproduce the financial scale, technical expertise and cross-border cooperation that have driven the HIV response.
The funding crisis is also placing scientific research infrastructure at risk.
Decades of international investment, particularly through US research institutions, have created laboratories, clinical trial networks and public health systems that extend far beyond HIV.
Those systems later supported vaccine, antibody and treatment research during the Covid-19 pandemic, demonstrating that HIV investment strengthens preparedness for wider global health emergencies.
Delegates therefore called for genuine technology transfer to help developing countries manufacture medicines and vaccines rather than remain permanently dependent on imported products.
Brazil’s experience was cited as an example. Long-term investment in institutions such as the Butantan Institute and Fiocruz allowed the country to develop and produce vaccines more rapidly when global supplies became constrained during the pandemic.
Speakers said similar capacity would be essential for ensuring affordable access to new HIV medicines and responding to future outbreaks.
The conference also heard warnings that funding cuts are being compounded by discrimination, misinformation and organised campaigns against the rights of vulnerable communities.
Erika Castellanos, executive director of Global Action for Trans Equality, said communities living with or most affected by HIV must be directly involved in decisions over programmes and financing.
“Fund this response like lives depend on it, because they do,” she said.
Global health leaders stressed that community organisations are often the only institutions able to reach people who avoid formal healthcare systems because of stigma, homophobia, transphobia or fear of criminalisation.
Cuts to such programs therefore risk driving the most vulnerable populations further from testing, prevention and treatment.
World Health Organization Director-General Dr Tedros Adhanom Ghebreyesus said sustained investment had already delivered historic progress.
Since 2010, AIDS-related deaths have fallen by 56%, new infections have declined by 43%, and 32.1 million people -- 78% of all those living with HIV -- now receive treatment.
But he warned that those achievements could be reversed if financing, political commitment and international solidarity continue to weaken.
Pan American Health Organization Director Dr Jarbas Barbosa said the central challenge was no longer a lack of scientific knowledge, but the failure to ensure equitable access to prevention, testing, treatment and care.
Welcoming delegates to the first International AIDS Conference held in South America, Brazilian Health Minister Alexandre Padilha delivered the same warning in starker terms.
“Innovation without access is not an innovation,” he said. “It is an injustice.”
The reports released in Rio show that the world is approaching a decisive crossroads.
After decades of investment, science has produced the medicines, data and delivery models capable of ending AIDS as a public health threat.
But as donor governments retreat and national health systems struggle to fill the gap, those advances risk remaining beyond the reach of millions.
The greatest threat to the HIV response is therefore no longer the absence of solutions, but the possibility that the world will stop paying for them.