Concerns over an HIV resurgence caused by strict drug laws fuelling an epidemic blamed on needle sharing dominated a world AIDS assembly that opened in Amsterdam on Monday.
Thousands of delegates - researchers, campaigners, activists and people living with the killer virus - gathered for a five-day war council amid dire warnings that complacency and a shortage of funds may yet cause AIDS to spiral out of control.
The 22nd International AIDS conference will seek to harness the star power of celebrity activists Charlize Theron, Elton John, and Prince Harry to bolster a battle that experts warn is losing ground in some parts of the world.
"In Eastern Europe and Central Asia new infections have increased 30 percent since 2010," International AIDS Society (IAS) president Linda-Gail Bekker said in the Dutch capital.
"This conference, we hope... will also shine a spotlight on this region, the only region in the world where HIV is rapidly increasing, in large part related to injecting drug use."
In recent days, experts have alerted that new HIV infections, while down overall, were rising in about 50 countries as global attention has waned and funding levelled off.
And many lamented that too sharp a focus on virus-suppressing treatment may have diverted attention from basic prevention programmes such as condom distribution, with the result that the AIDS-causing virus is still spreading easily among vulnerable groups.
"Despite all the remarkable advances that have been made, progress on ending AIDS is still slow," said Tedros Ghebreyesus, director general of the World Health Organization.
And he warned the world "will not" meet UN 2020 targets on HIV/AIDS, "because there are too many places in the world where people don't get prevention and treatment services they need."
Spread mainly through sex and blood contact, the immune system-attacking HIV virus has infected nearly 80 million people since the early 1980s.
More than 35 million have died.
"When I was born 20 years ago with HIV, the landscape of the epidemic looked very different to what it does now," said Mercy Ngulube, a youth activist attending the conference.
"It is so wonderful to be able to live a life where I don't have to wake up and wonder if we have the tools to fight HIV. But it is also sad to live a life where I know that we have the tools and I know that people cannot access them."
Last week, a UNAIDS report warned of a long and difficult road ahead.
New infections, though down, were still at 1.8 million last year, far short of the 500 000 annual ceiling the UN is targeting.
'No' to war on drugs
Yet despite the lag, reports show that donor and domestic funding has dropped "significantly" and will likely continue to decline.
According to UNAIDS, the funding gap is almost $7bn per year.
A major cause of the resurgence is the criminalisation of injecting drugs in many countries, particularly in eastern Europe and central Asia - including Russia.
This forces users onto the fringes of society and puts them at risk of infection through sharing soiled needles, then passing the virus on to their sexual partners.
"Close to half - more than 45 - percent of all new HIV infections in the world are in... the most affected and hard to reach groups, and that of course includes people who use drugs," said Chris Beyrer, director of the Center for Public Health and Human Rights at John Hopkins University.
"Progressive drug policy can really be a critical part of controlling the HIV epidemic," the former IAS president insisted.
NGOs at the conference are pushing a liberalisation campaign entitled: "Just say no to the war on drugs," a direct challenge to the 1980s Reagan administration's "Just say no" message at the height of the "war on drugs".