US researchers studied couples in nine countries and found that taking the drugs means men and women with HIV are much less infectious.
HIV is short for Human Immunodeficiency Virus, which causes AIDS. AIDS is short for Acquired Immune Deficiency Syndrome. There is no cure for AIDS, but cocktails of antiretroviral drugs can keep the disease at bay for many years and allow many infected people to live normal lives. The drugs work by suppressing HIV, which is classified as a retrovirus.
The landmark US study involved mostly heterosexual couples and found a 96 percent reduction in HIV transmission to a sexual partner when antiretroviral drug treatment began early, before a person's immune system was weakened by the virus.
People with HIV sometimes delay starting treatment with antiretroviral drugs until they develop serious AIDS-related illnesses (such as pneumonia). Sexual transmission accounts for about 80 percent of all new HIV infections. This study shows that starting treatment as early as possible would help cut the risk of passing on HIV through unsafe sex.