Smallpox Vaccine Safety
Smallpox is a contagious, disfiguring, and often deadly disease that is caused by the variola virus. Naturally occurring smallpox was eradicated worldwide by 1980 through a global immunization campaign. Smallpox vaccine is not currently recommended for the general public, although the vaccine is given to selected service members and laboratory workers. In the event of a smallpox emergency, the government has enough smallpox vaccine to vaccinate everyone in the United States.
The smallpox vaccine is safe, and it is effective at preventing smallpox disease. Vaccines, like any medicine, can have side effects.
Common Side Effects of Smallpox Vaccine
- Swollen lymph nodes
- Sore arm from the shot
- Body ache
- Mild rash
- Fatigue (tiredness)
- Problems with the vaccination site blister, such as infection
After getting the vaccine, a person will have a dime-sized lesion that gradually forms a scab and leaves a scar. The material from the lesion (fluid and crusts) is contagious until a scab forms at the vaccination site. Therefore, people who get the smallpox vaccine should be sure to properly care for and cover the vaccination site to prevent spreading the vaccine virus to other parts of their body or to other people.
Serious Side Effects of Smallpox Vaccine
- Heart problems
- Swelling of the brain or spinal cord
- Severe skin diseases
- Spreading the virus to other parts of the body or to another person
- Severe allergic reaction after vaccination
- Accidental infection of the eye (which may cause swelling of the cornea causing watery painful eyes and blurred vision, scarring of the cornea, and blindness)
The risks for serious smallpox vaccine side effects are greater for:
- People with any three of the following risk factors for heart disease: high blood pressure, high cholesterol, diabetes, high blood sugar, a family history of heart problems, or smoking
- People with heart or blood vessel problems, including angina, previous heart attack, artery disease, congestive heart failure, stroke, or other cardiac problems
- People with skin problems, such as eczema, atopic dermatitis, burns, impetigo, contact dermatitis, chickenpox, shingles, psoriasis, or uncontrolled acne
- People with weakened immune systems, such as those who have received a transplant, are HIV positive, are receiving treatment for cancer, or are taking medications that suppress the immune system
- Infants less than 1 year of age
- Women who are pregnant or breastfeeding
- People who are taking steroid eye drops or ointment
- People who have had problems after previous doses of smallpox vaccine or are allergic to any part of smallpox vaccine, such as antibiotics neomycin or polymixin B
Currently, there is one approved vaccine to protect people against smallpox:
- ACAM2000: The Food and Drug Administration approved this vaccine in 2007. The approval for the previously recommended smallpox vaccine (Dryvax) was withdrawn in 2008.
For more information about smallpox vaccine safety, visit:
- CDC’s Smallpox Vaccine Fact Sheet
- Smallpox Vaccine Medication Guide
- The Defense Health Agency’s Smallpox Vaccine Webpage
- Smallpox Vaccination and Adverse Events Training Module
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- Page last reviewed: January 21, 2016
- Page last updated: April 7, 2016
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