Aids experts warned on Tuesday that Africa should stop using a drug which has been hailed as one of the continent's best tools in fighting the HIV pandemic. They said the drug, nevirapine, which reduces the number of mothers transmitting the HIV virus to new-born babies, risks doing more harm than good. Single doses of nevirapine should make way for a much costlier but less risky alternative, said Sant'Egidio, an Italian non-governmental organisation. The single dose might be cheap and easy to administer, but nevirapine left too many babies born with HIV, did not extend the lives of mothers, and was responsible for growing resistance to other anti-Aids drugs, it was claimed.