New immunization strategies for children.

Childhood infectious diseases that can be prevented by immunization are no longer life-threatening but continue to impose a heavy public health burden in terms of morbidity and residual impairments. Diphtheria, tetanus, and poliomyelitis no longer pose risks to children. A dramatic decrease in Haemophilus influenzae type b infections has occurred since the introduction of a vaccine against this organism. In contrast, pertussis, measles, and mumps continue to affect several hundreds of thousands of children each year despite the availability of effective vaccines. Rubella remains inadequately controlled, and the incidence of congenital rubella syndrome is still unacceptably high. There is a need for developing methods capable of ensuring total population immunization, including education of parents and physicians, and the provision of free vaccines.