[Expanded program of vaccination. Results and prospects].

The expanded program on immunization, jointly launched by WHO and UNICEF in 1974 aimed in the beginning at immunizing 80% of the children of the world against measles, tetanus, pertussis, poliomyelitis, diphtheria and tuberculosis. After reaching the objectives in 1990, countries have been urged towards eradication of poliomyelitis, elimination of neonatal tetanus, and measles control. Immunization against hepatitis B and yellow fever were also proposed according to local epidemiology. Tremendous results have been already delivered: the American continent has eliminated poliomyelitis since August 1991, it has reduced dramatically the incidence of measles. All the countries, including those from Africa, are organizing campaigns aiming at polio eradication. Active surveillance systems have been implemented. But financial and operational constraints persist, linked to vaccines prices, their heat sensitivity, injection techniques, and to the sterilisation and waste disposal. Major efforts are still needed.