“Balancing Immunization Recommendations with Risk of Disease
Public health recommendations for immunization programs and practices represent a dynamic balance of risks and benefits. Vaccine safety monitoring is necessary to accurately weigh this balance and adjust immunization policy.
For example, monitoring of smallpox and oral polio vaccines being used in the United States as these diseases neared global eradication found complications associated with each vaccine that exceeded the risks of the diseases. This observation led to discontinuation of routine smallpox vaccination in the United States prior to global eradication and a shift from the oral poliovirus vaccine to a safer, inactivated poliovirus vaccine.”