PARIS, France (AFP) — International funding for the fight against HIV fell by nearly a fifth last year, the United Nations warned on Monday as a major AIDS conference began in Brazil.

The world’s response to the HIV epidemic is “absolutely faltering” after the biggest decline in funding in decades, UNAIDS Deputy Executive Director Angeli Achrekar told AFP.

The United States dramatically slashed foreign aid after Donald Trump returned to the White House last year, with European nations including France, Germany and the UK following suit.

International financing for HIV in developing countries fell by 18 per cent in 2025 alone, according to a UNAIDS report released at the 26th International AIDS Conference in Rio de Janeiro.

“If we do not collectively come together, as we have in the past, we will see re-emergence” of the virus, Achrekar warned.

Since 2011, HIV funding from European countries has fallen by 58 per cent, according to the report. As the European contribution decreased, the US share of the funding rose.

This meant that despite the sweeping cuts by the Trump Administration last year, the United States still provided 74 per cent of donor government funding, the report said.

Developing countries with the highest HIV rates — many of which are in sub-Saharan Africa — are meanwhile “stepping up”, Achrekar said.

Domestic HIV funding rose four per cent last year and now represents 60 per cent of all the total, according to the report.

However, these figures are still “a drop in the ocean” compared to what is needed, UNAIDS chief Winnie Byanyima told AFP last month.

Many low-income countries in Africa are dependent on overseas development assistance for 90 per cent of their HIV response, the report said.

Experts have cautioned that it is still too early to see the full impact of the funding cuts.

The number of new HIV cases and AIDS-related deaths dropped to their lowest levels in more than 30 years in 2025, according to the report.

New infections, however, rose in 21 countries, it added.

Achrekar called for the world to “use the momentum” from a political declaration adopted by the United Nations in late June that set out targets to end AIDS as a public health threat by 2030.

One of the goals is for 20 million people to have access to anti-retroviral drugs which prevent the spread of HIV.

Almost half of all children living with HIV were not receiving these drugs last year, the report warned.

Achrekar called on pharmaceutical firms, which make a range of new drugs seen as breakthroughs, to make them “accessible and affordable to all”.

Ahead of the conference in Rio, US pharma giant Merck announced plans to allow some manufacturers in Africa and India to make cheaper, generic versions of its once-monthly anti-retroviral pill Alimatravir, which has not yet been approved.

Also last week, Doctors Without Borders (MSF) called on US pharma company Gilead to make its preventative drug Lenacapavir — which has been hailed as a game-changer because it only needs to be injected twice a year — available to more nations in need.

Countries where clinical trials were held to test the drug — such as Brazil, Argentina, Mexico and Peru — are excluded from current deals allowing for the sale of generic versions, the NGO pointed out.

Research has shown Lenacapavir can be made for US$40 per person a year, but it costs up to US$28,000 per patient annually in the United States, MSF added.