The child had been born to a mother who was found to be HIV positive too late for anti-retroviral drugs to be administered to reduce the chance of passing on the infection to her baby.

The baby was given a strong dose of anti-retroviral drugs 30 hours after being born and doctors expected the baby to stay on the drugs for life.

But after 18 months the child disappeared and stopped taking the drugs.

The mother then came back five months later, her child was tested and doctors expected to find high levels of HIV – but the virus could not be detected.

That this case emerged at all is remarkable, because strategies in rich countries to prevent mothers infecting their unborn children stop transmission in about 98 percent of cases.

However, the UN says about 300,000 babies are born HIV positive in the developing world each year having acquired the infection in the womb.

So does the case of this child, who has not been identified but is said to come from the state of Mississippi, mean we can hope to find a cure for AIDS?

With us to discuss the likelihood are:

In London, Dr Pat Tookey, who is Principal Investigator for the UK and Ireland’s National Study of HIV in Pregnancy and Childhood

In Washington, Rob Sachs is joined by Yvonne Maldonado, Professor of Pediatrics and Infectious Diseases at Stanford University’s School of Medicine.

In Moscow, Elena Vovc, an HIV and AIDS Coordinator at the World Health Organization