Immunization: primary prevention par excellence.

Immunizing agents and vaccination programs have had a major impact on the health and longevity of our population. The continuation of established programs and the introduction of new programs will undoubtedly remain an integral part of our primary prevention activities. Decisions on the universal need for earlier immunizing agents were relatively straightforward, since most were directed at agents which were extremely communicable, and all were active against agents to which the population was fairly uniformly exposed. Because several of the "newer" vaccines do not meet these criteria, decisions on their use must be reviewed and may need to be based on other criteria. All decisions must take into account the risks and benefits of the vaccines. It must also be accepted that not all beneficial vaccines will necessarily become a part of universal immunization programs.