CDC answers questions about smallpox vaccine

Employees are likely to have a wide range of questions about caring for their injection site and protecting others from contracting the disease. Here are a few questions and answers provided by the Centers for Disease Control and Prevention (CDC). Other questions and answers are available on the CDC smallpox site at

Question: What is the optimal size of the semi-permeable dressing for the vaccination site?

Answer: The bandage should be large enough to cover the pustule or scab at the site of the vaccine and provide a barrier to vaccinia virus. In a recent study, the average size of the pustule at the vaccination site was half an inch, and the average size of the erythema, or swelling, at the vaccination site was two-thirds of an inch.

Question: Is there any particular risk for adverse reactions from people who wear contact lenses?

Answer: Vaccinia infection of the eye is a potentially serious complication of vaccination and can lead to altered vision. Therefore, all vaccinees need to be very careful to not inoculate the vaccinia into the eye. You should do several things to ensure you do not inoculate virus into your eye. Covering the vaccine site with gauze, tape, and a sleeved shirt or similar clothing, and careful hand washing decreases the chance of inadvertently getting vaccinia virus on your hands and possibly into your eye. Additionally, you should take extra care to wash your hands before handling your contact lenses.

Question: Is a history of no adverse reactions in childhood to smallpox vaccine a predictor of no or minor reactions to revaccination in adulthood?

Answer: No. Simply because a person did not experience an adverse reaction to the vaccine in childhood does not mean that he or she will not experience adverse reactions as an adult. Many of the conditions that increase the likelihood of serious adverse reactions may not have been present in childhood (e.g., skin conditions, taking medication that suppresses the immune system).

Question: Can I share a bed after vaccination?

Answer: Special care must be taken following vaccination with the smallpox vaccine to avoid contact spread of vaccinia. If specific precautions are followed, then individuals who have been vaccinated can share a bed with others. These precautions are: The vaccination site must be covered with a gauze bandage held in place with medical tape. As an extra precaution, the vaccinated person should wear a T-shirt or pajamas that cover the vaccination site. If the individual who has been vaccinated is not following these precautions then it is better not to share a bed. These precautions must be followed until the scab that forms at the site of the vaccination falls off on its own (two to three weeks).

Question: How should bed linens and clothing that has been in contact with the vaccination site be handled?

Answer: Clothing or any other material that may have come in contact with the vaccination site and could be contaminated with vaccinia should be handled with special care; a separate hamper should be used. Contact with these items should be kept to a minimum. They should be laundered in warm water with detergent and/or bleach. After handling, individuals should wash their hands thoroughly in warm water with soap or with an alcohol-based hand rub, such as a gel or foam. If hands are visibly contaminated with fluids from the vaccine, then individuals should wash with warm water and soap.

Question: Is it safe to have clothes that have covered the vaccine site dry-cleaned?

Answer: No. Vaccinia is spread by touching a vaccination site before it has healed or by touching bandages or clothing that have become contaminated with live virus from the vaccination site. After you get vaccinated, you must follow instructions for care of the vaccine site in order to avoid spreading vaccinia. (See CDC fact sheet.) This includes washing any clothing or other material that may have come in contact with the vaccine site in hot water with detergent and/or bleach. You should be able to launder any clothes that come in contact with the vaccine site in this way.

Question: Can I prepare food for others while my vaccination site is "active"?

Answer: Individuals who’ve been vaccinated can cook and clean normally as long as they wash their hands after contact with the vaccination site or any potentially contaminated materials.