Published in The Hindu on March 14, 2013
It is too early to celebrate the recent news of a breakthrough in the treatment of a baby infected with HIV. Despite the passage of a year after treatment for HIV was stopped and the viral load test returning negative results even at age 29 days, the Mississippi, U.S. baby cannot be described as being cured of HIV. Only a “functional cure” has been achieved at this point in time, which means the virus has not been able to rebound and replicate, and its activity remains undetectable even after treatment has been stopped. Traces of HIV DNA, incapable of replication, were found when last tested at age 26 months. At that time, only four copies of HIV DNA were detected per million peripheral blood mononuclear cells. This was eight-fold fewer than what was seen two months earlier, according to the abstract by Deborah Persaud, the lead author from the Johns Hopkins Children’s Center. The baby was given a cocktail of three antiretroviral drugs right from 30 hours of age and the treatment was continued till age 18 months. Now aged two-and-a-half years and being off treatment for the past one year, there are no signs of viral rebound. One plausible reason is that the early start of full-fledged treatment might have given insufficient time for the virus to form hideouts from where it could bounce back when treatment was stopped.
But there is good reason to be cautious interpreting the results. The first and biggest challenge that the researchers face is to conclusively prove that the baby was indeed infected with HIV. Also, the baby has to be followed-up for a longer time to assess the outcome of the treatment, as one year is too short a time to call the experiment a success. The lone case can serve as proof of concept to treat high-risk infants born to HIV-positive women if it finally emerges that the baby was truly infected with HIV, and early and aggressive intervention had brought about the functional cure. The next step will be to repeat it in other high-risk newborns to see if replicable and positive outcomes emerge. Vertical transmission accounts for up to 30 per cent of infection in children. But the risk can be cut to less than two per cent when protocols to prevent vertical transmission are adopted and strictly adhered to. For instance, in the U.S., where prenatal care to prevent vertical transmission is in place, fewer than 200 infants are born every year with the infection. Over 300,000 children are born HIV positive globally every year. So the priority should be to first target the low-hanging fruit by ensuring that simple measures to prevent infection are in place everywhere.