US Immunization Policy.

DURING THE PAST CENTURY, THE AVERAGE LIFE EXpectancy of US citizens increased by 30 years, primarily due to improvements in sanitation and development and use of vaccines and antimicrobial agents. Immunizations are one of the most cost-effective health intervention strategies available, saving society more than $5 for each dollar spent on most of the vaccines that are recommended routinely for children in the United States. At the end of the 20th century, the percentage of children younger than 2 years who received all vaccines in the recommended childhood immunization schedule was at a record high of about 90%. Immunization is one of the major public health achievements of the 20th century. Despite this remarkable success, the National Immunization Program has been subjected to increasing attacks by a number of individuals and groups. We highlight the benefits of the vaccines in the recommended childhood immunization schedule, discuss the known risks of vaccinations, explore some of the current impediments to a maximally effective national immunization program, and discuss challenges that lie ahead.