While the findings are encouraging, scientists warned they are not the definitive cure for HIV. It is thought to have been the speed and intensity of the action that knocked out HIV in the baby's blood before it could form hideouts in the body. But not all traces of the virus have been eradicated. Dr Deborah Persaud, of Johns Hopkins Children's Centre, who led the investigation, said that the child was in effect "functionally cured", meaning in long-term remission even if all traces of the virus haven't been eradicated.
The treatment would not work in older children or adults as the virus will have already infected cells. The number of babies born with HIV in developed countries has fallen dramatically with the advent of better drugs and prevention. Typically, women with HIV are given antiretroviral drugs during pregnancy to minimise the virus in their blood. Their babies go on courses of drugs, too, to reduce their risk of infection further. The strategy can stop around 98 per cent of HIV transmission from mother to child.
About 300,000 children were born with HIV in 2011. In the US such births are rare as HIV testing and treatment long have been part of prenatal care. "We can't promise to cure babies ... We can promise to prevent the vast majority of transmissions if the moms are tested during every pregnancy," said Dr Hannah Gay, of the University of Mississippi.
The only other person considered cured of the Aids virus underwent a bone marrow transplant from a donor naturally resistant to HIV.
Timothy Ray Brown, of San Francisco, has not needed HIV medications in the five years since that transplant.
The Mississippi case shows "there may be different cures for different populations of HIV-infected people", said Dr Rowena Johnston of amFAR, the Foundation for Aids Research.
That group funded Persaud's team to explore possible cases of paediatric cures. It also suggests that scientists should look at other children who've been treated since shortly after birth, including reports of possible cures in the late 1990s that were dismissed, said Dr Steven Deeks of the University of California, San Francisco.
Quick treatment
*A doctor gave the baby faster and stronger treatment than is usual, starting a three-drug infusion within 30 hours of birth.
*That fast action apparently knocked out HIV in the baby's blood before it could form hideouts in the body.
*Those so-called reservoirs of dormant cells usually rapidly reinfect anyone who stops medication.
-Independent