American Board of Internal Medicine (ABIM) Certification Practice Exam

For individuals with hematopoietic stem cell transplantation, when should the inactivated polio vaccination be given?

1. Before transplantation

2. Immediately after transplantation

3. 6-12 months after transplantation

4. Annually

The correct answer is: 6-12 months after transplantation

For individuals who have undergone hematopoietic stem cell transplantation, it is crucial to administer the inactivated polio vaccination at the appropriate time to ensure an effective immune response. The recommended time for this vaccination is typically 6 to 12 months after transplantation. After the transplant, patients often experience immunosuppression due to both the disease being treated and the conditioning regimen used before transplantation. This immunosuppression occurs in the months immediately following the procedure, which can compromise the body's ability to mount an effective immune response to vaccinations. Consequently, waiting 6 to 12 months allows for the recovery of the immune system to a point where vaccinations can be effective. In contrast, administration of the vaccine before transplantation may not provide adequate protection if the immune system is significantly compromised at that time. Immediate vaccination after transplantation would also be ineffective, as the immune system is still too weak to respond adequately. Annual vaccination is not recommended for polio in this context, as the timing focuses on immunologic recovery rather than a routine annual immunization schedule. Thus, the optimal timing aligns with ensuring a well-functioning immune response to vaccination.