The health minister, Fernand Ndjengbot, announced the launch of a mass vaccination programme against polio in late April, beginning with three days of concentrated action (April 25-27) and continuing over subsequent weeks. The nationwide campaign was designed radically to curb the incidence of an often crippling disease which afflicts 40% of children in the CAR. The main cause of polio's prevalence is the fact that barely one-third of children are given all the vaccinations on the UN World Health Organisation (WHO) recommended list, according to studies by the government statistics department. Some 55% of children receive between one and three of the vaccinations, but 18% have none at all. In urban areas around 58% of children are inoculated, while in rural areas the figure drops to less than one in four. Infants aged 12-23 months are the least vaccinated. The CAR is a predominantly rural society, but successive governments have failed to develop the effective grassroots primary healthcare networks pioneered in some even poorer rural states, such as Burkina Faso. Such networks can help prevent disease and provide rapid reporting of epidemics when they do occur. The last outbreak of German measles, which affected 60 children, of whom seven died, in the north-west early this year, was only reported after a month.