Researchers have profiled the HIV strains most likely to be transmitted during sex. The identification may help the hunt for vaccines to combat the most infectious strains.
A person who has been infected with HIV for several years harbours many slightly different strains of the virus, thanks to the virus's attempts to mutate and evade the immune system. Only one strain usually passes onto someone new, but scientists had little idea which strains those would be.
The results of a study conducted in Zambia suggest that transmitted strains tend to have a particular form of the protein called gp120 on their surfaces. This should be good news for those developing HIV vaccines, who may be able to target prototype vaccines more effectively against the most infectious strains of the virus.