Last year, researchers in Mississippi essentially "cured" an infant infected with HIV by giving the newborn a cocktail of medications normally reserved for advanced cases.
The child is now three years old, and the virus has not returned. Now there's word of a second, similar case.
Research presented at a meeting, highlights the case of an HIV infected baby in California, who received treatment within four hours of birth, and currently shows no signs of the virus.
However, the baby is still taking HIV drugs, and it is impossible to tell whether early treatment will have a long-term effect.
Thanks to good prenatal care and routine HIV testing of pregnant women in the US, cases of HIV transmissions from a mother to a newborn baby are rare, occurring in less than 200 cases a year.
Researchers want to study more babies to learn if early treatment stops the virus from taking hold in the body.