In just five years, the world's health authorities hope to declare an end to the AIDS epidemic.
But with a stroke of a pen, Donald Trump may have pushed that out of reach.
The US president's plan to slash foreign aid has derailed efforts to contain growing HIV epidemics in the Asia Pacific and caused some programs to be suspended.
The region has the largest HIV epidemic outside of Africa, with 300,000 new cases and 150,00 AIDS-related deaths in 2023.
And while "lifesaving" programs have been temporarily spared from a US funding freeze, advocates fear the impact of permanent cuts to prevention, education and outreach programs.
UNAIDS regional director Eamon Murphy said the US had provided more funding towards the cause than any other nation, as well as expertise in program delivery.
"We don't want to lose the critical support of the US," he said.
"All the decades of investment in the right programs and the right understanding of what's needed will be lost."
Is Asia falling behind in HIV prevention?
HIV is a virus that attacks the immune system and is transmitted by direct contact with body fluids such as blood, semen and breast milk.
Left untreated, the body becomes so weak and suspensible to life-threatening infections and cancer that a person can be diagnosed with AIDS.
HIV/AIDS has killed more than 42 million people since the 1980s, however, new treatments can effectively suppress HIV, prevent transmission and allow long and healthy lives.
While fewer people acquired HIV in 2023 across the world than at any time since the mid 1990s, progress is slowing in the Asia Pacific.
New cases declined just 13 per cent since 2010 compared to the global average of 39 per cent and there are growing epidemics in Papua New Guinea, the Philippines, Laos, Bangladesh and Afghanistan.
An estimated 6.7 million people are living with HIV across the region and some smaller nations like Fiji have been caught off guard by rising numbers.
Fiji Minister for Health Ratu Atonio Rabici Lalabalavu even declared an official "outbreak" in January to reflect "the alarming reality that HIV is evolving faster than our current services can cater for".
Mr Murphy from UNAIDS said the region needed more support to ensure countries could develop "sustainable" programs that take advantage of the latest science.
"We have a flatlining of the epidemic in Asia Pacific and so now is not the time to withdraw," he said.
How Trump could undermine Bush's legacy
Health and aid programs across the world were thrown into chaos last month after US President Donald Trump signed an executive order to freeze foreign aid for 90 days.
The move sparked fears for the future of the president's Emergency Plan for AIDS Relief (PEPFAR), which has invested more than $US110 billion in the global response to HIV/AIDS since it was founded by Republican former president George W Bush in 2003.
PEPFAR is credited with saving more than 26 million lives, supporting 20.5 million people with HIV treatment, preventing millions of new cases and financing 70 per cent of the global response to HIV/AIDS.
Felicity Young from Health Equity Matters was working in Washington DC when PEPFAR was established and said Americans "should be proud" of its success.
"It ushered in a whole new way of working in the HIV world, which has really grown from strength to strength," she said.
"So it's very distressing to see it dismantled in such a catastrophic and brutal way."
Following grave concerns from health professionals that the funding freeze could cause deaths, a subsequent "waiver" was announced to allow "lifesaving" activities to resume, such as HIV treatment, testing and efforts to prevent mother-to-child transmission.
But ambiguity surrounding what exactly is considered "lifesaving" has caused confusion among providers and clients in the Asia Pacific, where aid has tended to be more "strategic" rather than directly funding treatment.
Ms Young said education, inclusive care, law reform and stronger healthcare systems all helped ensure effective treatment.
"If all that work falls away, it'll be a very fragile system," she said.
"But I suspect many of the programs won't qualify for the waiver because they're not providing treatment.
"Programs are just stopping, so communities are being cut off."
Confusion sparks 'panic' in vulnerable communities
HIV advocate Maura Elaripe said there's been "a lot of misinformation" in Papua New Guinea about what services would actually be impacted by the funding freeze.
"The community is panicking that there won't be any drugs," she said.
Antiretroviral treatments, which suppress HIV and allow the immune systems to repair, have been crucial to reducing transmission, improving the quality of life and preventing AIDS-related deaths.
PNG's health department said in a joint-statement with UNAIDS that testing and treatment services remained available and the country had a 12 month supply of "essential HIV commodities", including antiretrovirals and testing kits.
"There is no shortage of HIV drugs and reagents in PNG," deputy secretary of public health Ken Wai said.
While the PNG government finances antiretroviral drugs and distributes them free of charge to about 50,000 people living with HIV, some clinicians, trackers and data entry clerks who support HIV services are funded by USAID.
Without that funding, proactive measures efforts targeting "key populations", such as men who have sex with men, transgender people and sex workers may disappear.
Ms Elaripe said losing those services would be a "big issue" and called on other funders to help fill the shortfall.
"We want Australia to step up," she said.
Who can fill the funding shortfall?
Australia has also been a long-standing funder of HIV programs across the Asia Pacific, including through the Indo-Pacific HIV Partnership signed with UNAIDS and Health Equity Matters last year.
The $12 million investment aims to strengthen health programs, promote harm reduction and build community capacity and adds to $25 million of previous funding for HIV initiatives.
The Department of Foreign Affairs and Trade did not answer questions about whether program it funds had been shut down or suspended as a result of the US funding freeze.
"Australia's development program is focused on being a partner of choice for our neighbours. This is fundamental to our region's prosperity, stability and security," a spokesperson said.
"The decision to pause United States foreign aid for policy review is a matter for the US Administration."
The department also did not say whether Australia was considering boosting its own contributions.
Given the fast-evolving changes to US policy under the Trump administration, the future of HIV and broader aid funding remains unclear.
Alongside PEPFAR, other programs heavily dependent on US funding could also be at risk, such as The Global Fund, which invests about $US5 billion every year to combat AIDS, Tuberculosis and Malaria.
Ms Young said she was not optimistic that other donors would be able to make up for the shortfall if the US did not reinstate funding, given its huge contribution.
"We're trying to work out who can adapt, who can respond and start to fill some of these areas," she said.
"But I suspect at the end of the day, some really tough choices are going to be made and some work will just fall away.
"Then we get loss of confidence from communities and the host country governments that we work with. The momentum just will disappear."
