For the last few years, AIDS experts have been arguing about the claim made forcefully by some Swiss scientists that giving anti-viral drugs to people with HIV also prevents transmission of the virus to others. While there had been some anecdotal and hypothetical evidence supporting this contention, there wasn’t much hard proof.
A Seattle team of scientists has now provided some pretty solid evidence, reported in the current issue of The Lancet.
“We found a 92 percent reduction in transmission among those who went on (drug therapy),” said Dr. Connie Celum, a leading AIDS prevention researcher at the University of Washington and senior author of the study.
Working in seven African countries (Botswana, Kenya, Rwanda, South Africa, Tanzania, Uganda and Zambia) with nearly 3,400 couples in which one partner is HIV-infected, Celum’s team followed 349 couples for two years after the infected partner qualified to begin taking anti-HIV drugs (ARVs, anti-retrovirals).
Standard procedure for starting ARVs is based on when the blood level of an immune cell targeted by HIV, known as the CD4 cell, drops below a certain threshold. In most African countries, that threshold is a CD4 count of 200 or lower (normal being from 500 to 1,000).
It’s worth noting, however, that there’s a fierce debate going on right now about whether it makes sense to use a higher threshold (of say 350, as is often done in the U.S.) or to just put people on ARVs as soon as they are infected. San Francisco’s Department of Health recently recommended that all HIV-infected people should get ARVs no matter what their CD4 count.
Of the couples in Celum’s study, only one of the HIV-infected partners on medication transmitted the virus to her partner as compared to 103 infections transmitted by HIV-positive partners not on ARVs.
Given that the AIDS pandemic is still on the increase and millions of those infected worldwide are still not receiving these life-saving drugs, the UW team’s findings give strong support to the urgent need for expanding access to drugs as an effective means to stop the spread of AIDS. Some experts say the spread of AIDS in Africa could be contained in as little as five years if everyone infected received treatment now.
AIDS activists used to chant “Treatment is Prevention” to make the case that people must be guaranteed access to treatment in order to encourage them to be tested and engage in prevention. Now, it appears that treatment is not simply a necessary partner to prevention. Science has shown that saving the life of an infected person is also a powerful method for preventing another infection.