The infant has now deemed "functionally cured," a condition that occurs when a patient achieves and maintains long-term viral remission without lifelong treatment and standard clinical tests fail to detect HIV replication in the blood. In contrast to a sterilizing cure, which is a complete eradication of all viral traces from the body, a functional cure occurs when viral presence is so minimal, it remains undetectable by standard clinical tests, yet discernible by ultrasensitive methods.

The investigators caution they don't have enough data to recommend change right now to the current practice of treating high-risk infants with prophylactic, rather than therapeutic, doses but the infant's case provides the rationale to start proof-of-principle studies in all high-risk newborns. "Our next step is to find out if this is a highly unusual response to very early antiretroviral therapy or something we can actually replicate in other high-risk newborns," said Dr Persaud. Dr Luzuriaga said that, "Complete viral eradication on a large scale is our long-term goal but, for now, remains out of reach, and our best chance may come from aggressive, timely and precisely targeted use of antiviral therapies in high-risk newborns as a way to achieve functional cure."

A single case of sterilizing cure has been reported so far. It occurred in an HIV-positive man treated with a bone marrow transplant for leukemia. The bone marrow cells came from a donor with a rare genetic mutation of the white blood cells that renders some people resistant to HIV, a benefit that transferred to the recipient. Such a complex treatment approach, however, is neither feasible nor practical.