Immunization is the most effective means of preventing Hepatitis A and B; influenza; measles, mumps, and rubella; polio; pertussis, tetanus, and diphtheria; varicella; and other vaccine-preventable diseases. In medical institutions, susceptibility among healthcare personnel to vaccine-preventable diseases can have devastating consequences. Any medical facility or organization that provides direct patient care is encouraged to formulate a comprehensive immunization policy for all healthcare personnel, as indicated by the Centers for Disease Control and Prevention (found at http://www.cdc.gov/vaccines/adults/rec-vac/hcw.html) and by the Advisory Committee on Immunization Practices (found at http://www.cdc.gov/vaccines/acip/).