A large scale malaria vaccine study led by the World Health Organization has been criticised by a leading bioethicist for committing a serious breach" of international ethical standards. The cluster randomised study in Africa is already under way in Malawi, Ghana, and Kenya, where 720,000 children will receive the RTS,S vaccine, known as Mosquirix, over the next two years. Mosquirix, the world's first licensed malaria vaccine, was positively reviewed by the European Medicines Agency, but its use is being limited to pilot implementation, in part to evaluate outstanding safety concerns that emerged from previous clinical trials. [Among these concerns] were a rate of meningitis in those receiving Mosquirix 10 times that of those who did not, increased cerebral malaria cases, and a doubling in the risk of death (from any cause) in girls. Charles Weijer, a bioethicist at Western University in Canada, told The BMJ that the failure to obtain informed consent from parents whose children are taking part in the study violates the Ottawa Statement, a consensus statement on the ethics of cluster randomised trials, of which Weijer is the lead author, and the Council for International Organizations of Medical Sciences' International Ethical Guidelines. "The failure to require informed consent is a serious breach of international ethical standards," he said.