AIDS Virus "Could Be Weakening"
October 5, 2005
A new study details the results of a comparison of HIV-1 samples from 1986-1989 and 2002-2003 conducted by a team at the Institute of Tropical Medicine in Antwerp. Researchers found the newer samples appeared not to multiply as well and were more sensitive to drugs.
Dr. Eric Artz said, "This was a very preliminary study, but we did find a pretty striking observation in that the viruses from the 2000s are much weaker than the viruses from the eighties.
"Obviously this virus is still causing death," Artz continued, "although it may be causing death at a slower rate of progression now. Maybe in another 50 to 60 years we might see this virus not causing death."
"What appears to be happening is that by the time HIV passes from one person to another, it has already toned down some of its most pathogenic effects in response to its host's immune system," said Keith Alcorn, senior editor at the HIV information charity NAM. "So the virus that is passed on is less 'fit' each time. This would suggest that over several generations, HIV could become less harmful to its human hosts. However, we are still far from that point; HIV is still a life-threatening infection."
The investigators compared only 12 samples from each time period, leading some experts such as Dr. Marco Vitoria, HIV expert at the World Health Organization, to question conclusions drawn from such a small study. Vitoria said other diseases such as smallpox, TB and syphilis had shown a tendency to weaken over time. He and the researchers stressed that people should not be lulled into a false sense of security nor should HIV prevention efforts be scaled down.
Other studies have suggested recent strains of HIV are becoming more resistant to drugs. "This latest study adds to the debate on an apparently confusing and contradictory issue," said Will Nutland of the charity Terrence Higgins Trust. What is clear, Nutland stressed, is that "HIV is showing no signs of dying out in the near future."
The report, "Replicative Fitness of Historical and Recent HIV-1 Isolates Suggests HIV-1 Attenuation Over Time," appeared in AIDS (2005;19(15):1555-1564).
This article was provided by CDC National Prevention Information Network. It is a part of the publication CDC HIV/Hepatitis/STD/TB Prevention News Update.