Drug Resistant HIV spreading globally

Drug resistant HIV is striking back against the antiretroviral drugs that keep it largely in check in rich countries, thanks both to its over-exposure to the major drugs and to individuals who don't realise (or care) they're infected and so spread resistant strains to new partners.

Its not new
Drug-resistant strains of HIV have already been documented in San Francisco and elsewhere in the US, and Europe. Now a model of their transmission, based on studies of gay San Francisco men, forecasts a rapid upsurge in the next five years.

What's more, as access to antiretroviral therapy is expected to expand in poorer countries, they could experience a rise in resistance too, predicts Sally Blower of the University of California, Los Angeles, lead author on the analysis.

Cocktail of resistance
Currently, people with HIV tend to be given a cocktail of drugs, making it less likely that resistance will emerge. That's because even if a strain evolves resistance to one of the drugs, it will still succumb to the others.

Short Term Thinking
However, the virus can evolve resistance nonetheless. Currently, about 15 per cent of new infections in San Francisco are from resistant strains, some of them resistant to all three major classes of drug used to combat the virus.

To see how this might increase in future, Blower's team created a model of HIV transmission that predicts how and when resistant strains will emerge. When they fed in data from San Francisco, it correctly predicted how drug-resistant HIV has already evolved and spread among gay men there over the past 20 years. It also predicted how quickly it will spread globally.

Full article here .....

Journal reference: Science, DOI: 10.1126/science.1180556