Efforts to vaccinate children in eastern Africa against polio have been so successful that the region is expected to be polio-free by 2000, according to the Centre for Disease Control and Prevention in Altanta, US. The incidence of polio in east Africa dropped by 91 per cent between 1988 and 1995, from 1813 to 160 cases. Mass vaccination campaigns, in which polio vaccine are given to under-fives across east African nations within the space of a few days have been particularly successful.