LONDON: Rapid evolution of HIV, the human immunodeficiency virus, is slowing its ability to cause AIDS, according to a study of more than 2,000 women in Africa. HIV is being “watered down” as it adapts to our immune systems, becoming less infectious, according to a new study from scientists in the UK.
The scientists then analyzed the impact on HIV virulence of the wide use of AIDS drugs. Using a mathematical model, they found that treating the sickest HIV patients — whose immune systems have been weakened by the infection — accelerates the evolution of variants of HIV with a weaker ability to replicate.
Scientists said the research suggests a less virulent HIV could be one of several factors contributing to a turning of the deadly pandemic, eventually leading to the end of AIDS.
Some 35 million people currently have HIV and AIDS has killed around 40 million people since it began spreading 30 years ago.
But campaigners noted on Monday that for the first time in the epidemic’s history, the annual number of new HIV infections is lower than the number of HIV positive people being added to those receiving treatment, meaning a crucial tipping point has been reached in reducing deaths from AIDS.
Previous research on HIV has shown that people with a gene known as HLA-B*57 can benefit from a protective effect against HIV and progress more slowly than usual to AIDS.
The scientists found that in Botswana, HIV has evolved to adapt to HLA-B*57 more than in South Africa, so patients no longer benefited from the protective effect. But they also found the cost of this adaptation for HIV is a reduced ability to replicate — making it less virulent.
The research also points out that increased access to antiretroviral therapy could contribute to an overall accelerated decline in HIV virulence over the coming decades.