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Smallpox vaccine Pregnancy and Breastfeeding Warnings

Smallpox vaccine is also known as: ACAM2000, Dryvax

Smallpox vaccine Pregnancy Warnings

A National Smallpox Vaccine in Pregnancy Registry has been established by the Centers for Disease Control, Food and Drug Administration, and Department of Defense to collect reports of exposure to vaccine during pregnancy. As of April 2003, there have been 103 reports of inadvertent exposure. Of 6 women who were exposed to vaccine during pregnancy or conceived within 4 weeks after vaccination, two had miscarriages. Two pregnant women had close contacts who were recently vaccinated; however, neither had symptoms of vaccinia exposure.

Smallpox vaccine has been assigned to pregnancy category C by the FDA. Animal studies have not been reported. The vaccine is not known to be teratogenic. Vaccinia virus may very rarely cause fetal infections after vaccination, resulting in stillbirth or neonatal death. Less than 50 cases of fetal vaccinia have been reported. In a nonemergency situation, pregnant women or women who may become pregnant within 4 weeks of vaccination, who have not been exposed to smallpox, should not be routinely vaccinated until after delivery. Close contacts of pregnant women (household or sexual contacts) should also not be routinely vaccinated. However, the vaccine should be administered to pregnant women who have been exposed to smallpox. There are no contraindications to receiving the vaccine in case of an outbreak emergency. Because the risk of maternal serious illness or death, prematurity, miscarriage, or stillbirth from a smallpox infection are greater than the risk of the vaccination, smallpox vaccine is recommended and should be offered to pregnant women in case of an outbreak emergency.

See references

Smallpox vaccine Breastfeeding Warnings

There are no data on the excretion of smallpox vaccine antigens or antibodies into human milk. The vaccine is not recommended for lactating mothers in nonemergency situations.

Tertiary contact vaccinia has been reported in a breast-feeding infant of a wife of a vaccinee (the father). The vaccinee had a normal primary reaction on days 6 to 8 after vaccination. The mother developed vesicles on both areolas approximately 2 weeks after her husband was vaccinated, but continued to breast-feed. The infant started developing lesions 25 days after the father's vaccination, which were confirmed to be contact vaccinia. The Centers for Disease Control and Prevention have stated that it is safe for a mother to breast-feed after a close household contact is vaccinated, as long as standard precautions to prevent contact spread (handwashing, vaccination site care) are followed.

See references

References for pregnancy information

  1. Rotz LD, Damon IK, Becher JA "Vaccinia (smallpox) vaccine recommendations of the advisory committee on immunization practices (ACIP)." MMWR Morb Mortal Wkly Rep 50(RR 10) (2002): 1-25
  2. CDC. Centers for Disease Control and Prevention "Smallpox vaccination clinic guide. Logistical considerations and guidance for state and local planning for emergency, large-scale, voluntary administration of smallpox vaccine in response to a smallpox outbreak. Available from: URL:" ([2002 Oct 16]):
  3. "Product Information. Dryvax (smallpox vaccine)." Wyeth-Ayerst Laboratories, Philadelphia, PA.

References for breastfeeding information

  1. "Product Information. Dryvax (smallpox vaccine)." Wyeth-Ayerst Laboratories, Philadelphia, PA.
  2. Garde V, Harper D, Fairchok MP "Tertiary contact vaccinia in a breastfeeding infant." JAMA 291 (2004): 725-7

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