The research team looked specifically at HIV in Botswana and South Africa. It found that over time, human immune system proteins, in addition to the use of HIV drugs, may have forced the virus to change into less virulent forms.
This is consistent with the theory that viruses get less virulent over time. The optimal evolutionary strategy for a virus is to be infectious (so it creates more copies of itself) but non-lethal (so its host population doesn’t die out). The "poster boy" for successful long-living viruses is, arguably, the family of viruses that cause the common cold, which has existed for thousands of years.
Similarly, this study does not show that HIV virulence in the UK is decreasing, and that the virus remains life-threatening.
The simplest way to protect yourself against HIV infection in the UK is to use a condom during sex and never share needles if you are an injecting drug user.
The study was led by researchers from Oxford and several institutes in Canada, the US, South Africa, Botswana and Japan. It was funded by grants from the National Institutes of Health (US), the Wellcome Trust (UK), the Medical Research Council UK and the Canadian Institutes of Health.
The study was published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS), a peer-reviewed science journal. It is an open-access study, meaning that anyone can read it online or download it for free.
The UK media reported the story accurately. It was important that they included a warning that, despite a small decrease in the virus’ potency in some areas of Africa, HIV still causes AIDS. This can significantly shorten life, due to impairment of the immune system if the correct treatment is not followed and made available soon after infection.
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