Over 3 million deaths from measles, neonatal tetanus and pertussis are prevented by vaccination each year. In the Americas, poliomyelitis has been eliminated, and measles is close to elimination. Globally, reported poliomyelitis incidence has declined by over 80% since 1988. Strategies have evolved from strengthening routine childhood immunization services, to establishing disease surveillance and defining specific activities for disease control and elimination. Efforts to ensure the supply and quality of vaccines are underway. New vaccines against major pathogens will be licensed soon. Some of these will be used for groups other than mothers and infants, requiring re-definition of the 'EPI target groups'. Despite global successes, in 1995, six of the world's most populous developing countries reported coverage levels below 70% and coverage is below 50% in several African countries. Immunization programmes will need to be tailored to the level of economic and health systems development of a country. Industrialized countries must offer sustained support to expand immunization programmes in ways that strengthen health systems in developing countries.