Even today, the most effective vaccines are live attenuated viruses, which replicate in the host and produce immunity to pathogenic viruses without causing disease. Other effective immunizing agents include inactivated or killed viruses, bacterial toxoids, capsular antigens, synthetic vaccines produced by recombinant DNA technology, and passive immunization with immunoglobulins or immune serum. The enormous benefits of immunization are obvious. In 1980, the World Health Organization declared that smallpox had been completely eradicated by means of an aggressive global immunization program. The recent recognition of pertussis in adults is another example of the importance of maintaining the protection afforded by vaccines throughout life.
Individual practitioners can do much to increase utilization of available products.
Whereas pediatricians are traditionally diligent in offering immunizations, internists too often overlook the importance of routine immunization in adults. For example, more than 87 percent of children between six and 11 years of age have antibodies against tetanus, but fewer than 28 percent of Americans older than 70 years have similar protection. Influenza and pneumococcal vaccines are also underutilized. Except for travelers, few patients request immunization. Therefore, the physician must initiate the process by taking a detailed immunization history, including any adverse reactions and possible egg allergies.