One of the most worrying and depressing features of the AIDS virus is that it appears to leave its victims infected, and able to infect others, for life. So there was great excitement back in March when it appeared that a little American girl, born with the virus, had been cured by retroviral drugs.
These medicines are able to keep the virus in check, but it had always seemed that once treatment stopped, the disease would advance again. Then along came the ‘Mississippi baby’ who was treated within a few hours of birth, with apparently dramatic results.
The shattering of these hopes with the reappearance of the virus in the four year old has been "obviously disappointing" in the words of Dr Anthony Fauci, director of the USA’s National Institute of Allergy and Infectious Diseases.
The world has made progress on reducing the number of people newly infected with AIDS. In 2012, the figure was 2.3 million, down by a third since 2001, but that still leaves more than 35 million people across the world living with the disease.