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Smallpox vaccine Pregnancy and Breastfeeding Warnings

Medically reviewed by Last updated on Aug 16, 2022.

Smallpox vaccine is also known as: ACAM2000, Dryvax

Smallpox vaccine Pregnancy Warnings

Animal studies are not available. There are no controlled data in human pregnancy.

Health care providers should report to the National Smallpox Vaccine in Pregnancy Registry all pregnant patients who from 42 days prior to conception onward those who receive the vaccine, or who had close contact with a vaccinee within the previous 28 days.

AU TGA pregnancy category D: Drugs which have caused, are suspected to have caused or may be expected to cause, an increased incidence of human fetal malformations or irreversible damage. These drugs may also have adverse pharmacological effects. Accompanying texts should be consulted for further details.

US FDA pregnancy category D: There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

Use is not recommended unless smallpox exposure is considered likely.

AU TGA pregnancy category: D
US FDA pregnancy category: D

-Live vaccinia virus vaccines may cause fetal harm when administered during pregnancy; generalized vaccinia of the fetus, early delivery of stillborn infant, or high risk of perinatal death have been reported.
-Although risk may be low, congenital infection has been reported, principally occurring during the first trimester.
-Only vaccinate if exposure is considered likely; if used during pregnancy or the vaccinee has close contact with a pregnant person, inform the pregnant person should be informed of the risk to the fetus.

See references

Smallpox vaccine Breastfeeding Warnings

Use is not recommended.

Excreted into human milk: Unknown
Excreted into animal milk: Data not available

-There is no information regarding this vaccine virus or antibodies on the presence in human milk.
-Live vaccinia virus may be inadvertently transmitted to the infant.
-Infants are at high risk of serious complications from live vaccinia smallpox vaccination.
-The Centers for Disease Control and Prevention (CDC) recommends against vaccinating nursing patients, including those pumping and feeding via a bottle.
-If a lactating patient is vaccinated, it is recommended to avoid breastfeeding or handling any infant for at least 3 to 4 weeks until the vaccination scab has separated from the vaccination site.
-Breast milk may be pumped to maintain the milk supply, but the milk should be discarded.

See references

References for pregnancy information

  1. Product Information. ACAM2000 (smallpox vaccine). Emergent BioSolutions Inc. 2020.

References for breastfeeding information

  1. National Library of Medicine (US). Drugs and Lactation Database (LactMed) 2019.
  2. Product Information. ACAM2000 (smallpox vaccine). Emergent BioSolutions Inc. 2020.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.