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Notice to Readers: National Smallpox Vaccine in Pregnancy Registry

Smallpox vaccine is known to cause fetal vaccinia, a very rare but serious complication of exposure to smallpox vaccine during pregnancy. Fewer than 50 cases have been reported (1--3), three of which occurred in the United States in 1924, 1959, and 1968. Affected pregnancies have been reported in women vaccinated in all three trimesters, in primary vaccinees, and in those being revaccinated, and in nonvaccinated contacts of vaccinees. Because a risk for infection to the fetus is possible in the pre-event setting, smallpox vaccination is not recommended for pregnant women or anyone with close physical contact to a pregnant woman (e.g., a household member or sex partner).

CDC has established the National Smallpox Vaccine in Pregnancy Registry, a surveillance system to monitor the outcomes in women who inadvertently received smallpox vaccine during pregnancy, became pregnant within 28 days after vaccination, were a close contact with a vaccinee within 28 days. Exposed pregnant women should contact their health-care providers or their state health department for assistance in enrolling in the registry. Health-care providers and staff from state health departments are encouraged to report all exposed pregnant women to the registry. Reports should be routed through CDC, telephone 877-554-4625 or 404-639-8253.


  1. Lane JM, Millar JD, Neff JM. Smallpox and smallpox vaccination policy. Annu Rev Med 1971;22:251--72.
  2. CDC. Smallpox vaccine: recommendations of the Public Health Service Immunization Practices Advisory Committee. MMWR 1978;27:156--8,163--4.
  3. CDC. Adverse reactions to smallpox vaccination---1978. MMWR 1979;28:265--7.

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