A baby born with the virus that causes Aids appears to have been cured, scientists have announced.
Specialists at a major Aids meeting in Atlanta, Georgia, described the case of a child from Mississippi who is now two-and-a-half and has been off medication for about a year with no signs of infection.
There is no guarantee the child will remain healthy, although sophisticated testing uncovered just traces of the virus' genetic material still lingering. If so, it would be only the world's second reported cure.
Experts say the announcement offers promising clues for efforts to eliminate HIV infection in children, especially in Aids-plagued African countries where too many babies are born with the virus.
"You could call this about as close to a cure, if not a cure, that we've seen," Dr Anthony Fauci of the National Institutes of Health said.
A doctor gave the baby faster and stronger treatment than usual, starting a three-drug infusion within 30 hours of birth. That was before tests confirmed the infant was infected and not just at risk from a mother whose HIV was not diagnosed until she was in labour.
"I just felt like this baby was at higher-than-normal risk, and deserved our best shot," Dr Hannah Gay, a paediatric HIV specialist at the University of Mississippi, said.
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, said Dr Deborah Persaud of Johns Hopkins Children's Centre.
She led the investigation that deemed the child "functionally cured", meaning in long-term remission even if all traces of the virus have not been completely eradicated.
Dr Persaud's team is now planning a study to try to prove that, with more aggressive treatment of other high-risk babies. "Maybe we'll be able to block this reservoir seeding," she said.