Its been 25 years since the human immunodeficiency virus (HIV) was discovered, but the pandemic continues unabated. Researchers are calling for new ideas to tackle the scrounge.
Men and women in the front line of the combat said there had been some remarkable successes in fighting AIDS.
They hailed the swift identification of the pathogen that causes acquired immunodeficiency syndrome (AIDS) and the advent of the "triple cocktail" of drugs in the mid-1990s that transformed a death sentence into a manageable disease.
But they also spoke of cruel setbacks.
These include the search for a vaccine -- the only way of stopping the global pandemic -- and an HIV-blocking vaginal gel to shield women.
Such failures show basic questions remain to be answered about HIV's shape-shifting properties and its stealthy invasion of immune cells, they said.
"We still don't completely understand the various forms of the virus. It's more complicated for us than we thought," said France's Luc Montagnier, who with Robert Gallo of the United States identified HIV as the cause of AIDS.
"We need to go back to the question of basic research, to have new ideas, new teams, to take a new look at cellular biology," said Jean-Francois Delfraissy, director of France's National Agency for AIDS Research (ANRS).
Alice Dautry, head of the Pasteur Institute, said the next phase of AIDS research called for "a multidisciplinary approach, for looking at the problem through different eyes. When there is a problem, it has to be attacked from every direction."
Gallo called for a rethink of vaccine strategy in the light of two bad flops in this field.
Of the prototype vaccines are in the pipeline, many would be a waste of money and precious resources and could discourage volunteers from taking part, if they were put into costly, large-scale trials, Gallo said.
"Some fundamental biological questions are needed (to be addressed) before some vaccines go forward, or we tend to waste money, produce a depressing atmosphere in the field and take money away from the basic science that is needed right now," he said.
AIDS emerged as a new disease in 1981, initially among US homosexuals. Today, the disease has claimed around 25 million lives and another 33 million are infected.
Gallo attacked what he called a worrying tendency to sideline AIDS as a manageable disease in the age of antiretroviral drugs.
Only a fraction of people living in Africa who need the lifeline therapy actually receive it, he said.
"The [2004 Indian Ocean] tsunami made great headlines, as it should have -- 200,000 people died in one month," he told a press conference at the Pasteur Institute as the three-day meeting got underway.
"But every month, there's an AIDS tsunami -- 200,000 people die of AIDS. Do you think it gets the attention it deserves?"
On May 20 1983, Montagnier's team at the Pasteur Institute published a paper in the US journal Science, describing a virus found in a patient who died of AIDS. Gallo later demonstrated that a virus, found to be the same one isolated by Montagnier, caused the disease.
For several years, an often-bitter dispute unfolded as to who was the first to discover the virus, culminating in a 1987 settlement at top political level under which the duo shared the credit.
"As far as I'm concerned, (the row) was settled over 20 years ago, completely, in every respect," said Gallo, pointing out that he and Montagnier co-authored research papers these days.
Montagnier said he was "completely in agreement... there were legal problems, problems about intellectual property that were resolved above our heads."