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Smallpox Vaccine-Associated Adverse Events

DoD Smallpox Vaccination Program Resource Center

Smallpox vaccine is made from a live virus called "vaccinia." This live virus helps the body develop immunity to smallpox disease. When you receive smallpox vaccine, the smallpox vaccination site contains a very small amount of vaccinia, which can be spread to other people. Accidental spread of vaccinia from the vaccinated person to an unvaccinated person (contact) is known as contact transmission.

Transmission can occur from the time you receive the vaccine until the vaccination site is completely healed (the skin under the vaccination site scab looks like the rest of the skin on the arm). The virus can spread by touching yourself after touching the vaccination site or touching items that have touched the vaccination site, such as bandages, clothes, sheets or towels. Common areas affected are the face, hands, and genitalia.

High-risk individuals must avoid close contact* with someone who has received the smallpox vaccine. Those at high-risk of contact transmission include:

  • Pregnant women and women who are breastfeeding.
  • People who have or have had chronic skin conditions like eczema or atopic dermatitis.
  • People who have breaks in their skin from conditions such as severe acne, shingles, poison ivy, burns, impetigo, or other rashes.
  • People with weakened immune systems (people who have received a transplant, are HIV positive, are receiving treatment for cancer, or who are taking high doses of steroids).
  • Infants younger than 12 months old.

The Department of Defense recommends that people who receive smallpox vaccine who live with a high-risk close contact obtain alternate lodging.

*Close contact includes sexual activity, sharing a bed, bathing, contact sports activities, and rough-housing.

Contact Transmission


-- The contact develops a sore or sores that look like the vaccinee's smallpox vaccination site.

-- The contact may also have fever, enlarged lymph nodes headache, and body aches.

-- In people with certain medical conditions, there is a risk of more serious adverse events occurring as a result of contact transmission. An example is exzema vaccinatum, a serious infection that can be deadly. 


-- The sore or sores that result from contact with a person who has received smallpox vaccine usually do not require treatment and resolve after 2-3 weeks.

-- Sores are infectious and should be covered until the skin at the at the sore site looks like the rest of the skin.

-- Submit a Vaccine Adverse Events Reporting System (VAERS) report.


-- Change your own dressing following smallpox site care instructions. Wash your hands before and after changing your dressing, and properly dispose of your dressing.

-- Keep your site covered when around unvaccinated contacts. In addition to the bandage, wear a sleeved shirt.

-- Do not share clothing or towels.

-- For more information, please read "What You Need to Know About Smallpox Vaccine."

Family Members/Close Contacts

-- Do not touch the vaccination site or items that have touched the vaccination site, such as bandages, clothing, towels, wash clothes, and sheets.

-- If you accidentally touch the vaccination site or something that has come in contact with the site, immediately wash your hands and the area that was touched with warm water and soap. DO NOT touch your eyes or any other body part before you wash your hands.

-- If you share a bed with the vaccinee, be sure that he or she has a dressing covering the vaccination site until the skin has healed. Additionally, the vaccinee should wear a long sleeve shirt or pajamas that cover the bandage.

-- Do not share clothing or towels.

-- Machine wash items that have touched the vaccination site with hot water and detergent and/or bleach.

-- Remind the vaccinee to follow the instructions he or she received regarding site care and hand washing.

-- If you develop a sore or rash, seek medical attention. Make sure to tell your provider that you have been in contact with someone who has received the smallpox vaccine.

-- For more information about proper vaccination site care, please see the ACAM2000 Medication Guide.

Support CenterIf you have questions or concerns, discuss them with a provider and contact the Worldwide DHA Immunization Healthcare Support Center.

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