Answer. The smallpox vaccine is made from a live virus called vaccinia that helps the body develop immunity to smallpox. The vaccine does not contain the smallpox virus and it cannot cause smallpox. However, the smallpox vaccine is made from a live virus and it can cause complications in people who are taking medications to prevent rejection of a transplanted organ. Consequently, kidney transplant patients should not receive a smallpox vaccination.

Smallpox vaccination causes a skin ulcer at the site of vaccination and sometimes small skin ulcers elsewhere. These small sores shed vaccinia virus for up to 20 days after vaccination. This shedding can cause infection with the vaccinia virus in people who are susceptible. However, transmission requires close contact.  Persons who live with organ transplant patients should avoid smallpox vaccination, if possible. If vaccination is required, transplant patients should not have direct contact with anyone who has been vaccinated until the scab over the vaccination site is gone. This usually takes about three weeks.

Dialysis patients and patients with chronic kidney disease also have a weakened immune system. We don't know how risky exposure to the vaccinia virus used for smallpox vaccination is for dialysis patients or those with kidney disease. At least for now, it is not recommended that dialysis patients or patients with other chronic diseases be vaccinated against smallpox. It would be a good idea for dialysis patients and patients with chronic kidney disease to avoid direct contact with anyone who has been vaccinated within the past three weeks. When contact is unavoidable, the vaccination site should be well covered with a bandage and protective clothing. Vaccinated health care workers who have contact with dialysis patients and those with chronic kidney disease should use thorough, frequent hand washing. It would be best if vaccinated individuals did not participate in the direct medical care of transplant patients for three weeks after vaccination.

Answer provided by George Aronoff, MD, FACP, a Professor of Medicine and Pharmacology and Chief, Division of Nephrology at the University of Louisville School of Medicine. Dr. Aronoff is a member of the AAKP Medical Advisory Board. 

The American Association of Kidney Patients presents Ask the Doctor, an opportunity for readers to submit kidney related health questions to healthcare professionals who specialize in an area of concern. The answers are not to be construed as a diagnosis and therefore, alterations in current healthcare should not occur until the patient’s physician is consulted.

This article originally appeared in the March/April 2003 issue of Kidney Beginnings: The Magazine, Vol. 2, No. 1.

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