Researchers from the Wellcome Trust set out to study the older children arriving at a clinic in Harare, Zimbabwe, and have demonstrated that the numbers are significant. Half a million babies are estimated to have been infected with HIV at birth or during breastfeeding last year alone. The Zimbabwe study suggests as many as one in four may survive into adolescence.
"The findings are quite extraordinary," said Dr Liz Corbett, a Wellcome Trust senior clinical fellow in tropical medicine from the London School of Hygiene and Tropical Medicine, based in Zimbabwe.