Assessment: Neurologic risk of immunization [RETIRED]

Immunization programs are among the most cost-effective public health measures. They are the first line of defense against infectious disease, and when abandoned, epidemics often follow. Vaccines are biological products and some differences exist from lot to lot. Although no vaccine is 100% effective or safe, modern vaccines have an excellent safety record. Smallpox was eradicated by a global immunization program, and the eradication of poliomyelitis is within reach for the year 2000. Physicians are quick to blame vaccines for adverse neurologic events that follow immunizations. This bias probably originated with the first vaccines for rabies. They were grown in the CNS of mature animals, contained myelin basic protein, and often caused encephalomyelitis. In fact, no vaccine currently licensed for use in the United States is known to cause or exacerbate a demyelinating disorder of the CNS.