Since the launch of the Global Polio Eradication Initiative in 1988, there has been a spectacular drop in the number of cases of polio each year:

The rise in the number of cases in 2002 may be explained by inadequate immunization campaigns in India and Nigeria, and by improved reporting of patients with the disease. The WHO has taken measures to correct the situation (see page on the Global Initiative) and in 2003 the incidence of polio appears to be declining in India, where three-fourths of all cases were located in 2002.