Vaccination during pregnancy.

QUESTION: One of my patients is studying to become a dental hygienist. Owing to the program requirements, she received several vaccinations last week, including measles-mumps-rubella, varicella, and hepatitis B (HB) vaccines, as well as a tetanus booster. However, today a blood test confirmed that she is currently 6 weeks pregnant. What is known about the safety of these vaccines during pregnancy, and are there any general recommendations for vaccines for women who are planning to become pregnant or who are currently pregnant? ANSWER: The combination measles-mumps-rubella vaccine and the varicella vaccine are live attenuated vaccines, and are contraindicated during pregnancy owing to theoretical concerns. However, there is no evidence that there are increased risks of malformations, congenital rubella syndrome, or varicella syndrome attributable to these vaccines. The HB and tetanus vaccines are composed of noninfectious particles or toxoids, and theoretically should cause no increased risk to the developing fetus. In addition, limited observational data also support no increased risk of any adverse pregnancy outcomes; consequently, administration of the HB and tetanus vaccines might be, if indicated, considered during pregnancy.