Scientists meeting in Paris on Monday for a council of war on the Aids pandemic were lauded for the strides they had made during a two-decade-old campaign, but were also told they faced a foe unique in its stealth and tenacity.
The quest for knowledge about the human immunodeficiency virus (HIV) has been an ”extraordinary journey,” said Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases (NIAID) and a top Aids authority.
He sketched an odyssey that began in 1981, when epidemiologists spotted a bizarre scattering of deaths among previously healthy homosexuals in New York and California, who had died from opportunistic diseases, their immune systems irrevocably destroyed.
Within months, there was a terrifying realisation: this was a previously unidentified disease that was already secretly reaping lives in sub-Saharan Africa, Fauci said.
Then in 1983, French researchers made a great breakthrough: they pinpointed HIV as the cause of Aids — a virus, transmitted through sexual contact, shared use of drug needles or contaminated blood transfusions, which infected cells in the immune system, then replicated crazily and destroyed their host.
That discovery opened the way to a test for HIV, which was vital for devising prevention strategies, and to sequencing the agent, thus laying bare its workings at a molecular level, Fauci said.
In the mid-1980s came the first generation of HIV drugs, followed a decade later by highly active anti-retroviral therapy (Haart) — the powerful but costly HIV ”cocktail” that has enabled infected people in the rich world to turn HIV/Aids from a mortal to
a manageable disease.
Today, a third generation of drugs, called fusion inhibitors, is targeting the virus at a different part of the infection cycle.
”We probably know more about HIV pathogenesis than we do about any viral disease pathogenesis, but there are some important gaps in our knowledge that we still in the coming decade need to learn much more about,” Fauci said at a press conference, prior to his keynote speech at the conference.
HIV ”is unique,” Fauci said.
There has never been a documented case, he noted, of a human being clearing out HIV thanks to a response to the immune system — the complex defences of antibodies and white blood cells that swarm out and destroy an invader.
”Science is going to have to bridge that gap,” he said.
Fauci said there were two main reasons why HIV had foxed attempts to destroy it with drugs or devise a vaccine to prevent infection in the first place. The first was the virus’s ability to enter an immune cell and slyly integrate with its genome, essentially shielding itself from surveillance.
”Almost every other virus that we have certainly infects cells by a particular receptor, proliferates, kills cells but it leaves some very vulnerable pathways along its replication cycle for the body’s immune system to prevent infection or clear infection as well as therapeutic targets.
”The other capability that it has … is its extraordinary capability of mutating,” he said.
”It replicates at a very very high rate and it’s an RNA virus that has a very poor proof-reading mechanism, namely to allow it to replicate the way it was in the previous generation. Because of that, it changes every time it replicates.”
That extraordinary mutability made it a shifting target for vaccine engineers, Faudi said.
The four-day meeting, gathering thousands of researchers, began on Sunday. It is the biggest Aids conference this year, and its roster of speakers on Monday included former South African president Nelson Mandela, an iconic figure for Aids campaigners.
At least 60-million people have become infected with HIV since 1981, more than a third of whom have died, according to the agency UNAids. – Sapa-AFP