The seven major childhood infectious diseases-measles, mumps, rubella, polio, diphtheria, pertussis, and tetanus-can cause permanent disability and, in some cases, death. They all can be prevented by immunization, but prior to the National Childhood Immunization Initiative of 1977 more than a third of all children under age 15 were not properly protected. And even though vaccines are now available to reduce the risk of influenza, hepatitis B, and pneumococcal pneumonia, many high risk patients are not protected. Outbreaks of measles and pertussis, and occasionally of diphtheria and polio, during the mid-1970s indicate that immunization must be emphasized continually. With the combination of safe, effective vaccines, public and private programs, and a reliable disease surveillance and outbreak containment system, infectious diseases can be controlled. The Department of Health and Human Services has proposed a major initiative designed to eliminate the indigenous occurrence of measles.