American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the recommendation for Haemophilus influenzae type B vaccination in patients undergoing hematopoietic stem cell transplantation?

1. 3 doses 6-12 months after transplantation

2. Immediately after transplantation

3. Once a year

4. Not recommended

The correct answer is: 3 doses 6-12 months after transplantation

The recommendation for Haemophilus influenzae type B (Hib) vaccination in patients undergoing hematopoietic stem cell transplantation is to administer three doses 6-12 months after transplantation. This timing is essential due to the immunocompromised state that patients experience immediately after transplantation. During the initial months post-transplantation, patients are at a heightened risk for infections due to the immunosuppressive therapies and the procedure itself. As a result, it is crucial to delay live or inactivated vaccinations until the patient's immune system has sufficiently recovered, which typically occurs around 6-12 months post-transplant. Administering the Hib vaccine during this period helps ensure that the patient can generate an adequate immune response, providing protection against infections caused by this bacterium, which can be particularly severe in immunocompromised populations. The other options, such as vaccinating immediately after transplantation, would not be advisable because the patient's immune system may not be fully functional, reducing the effectiveness of the vaccine. Yearly vaccinations are generally not recommended for Hib, as the vaccination schedule focuses on a primary series for immunization rather than maintenance doses. Lastly, stating that vaccination is not recommended would ignore the importance of protection against infections for these patients, particularly