Which vaccines should be avoided in patients receiving chemotherapy?
This is a frequent question in many oncology practices and infusion centers. I suggest thinking of vaccines as being in 1 of 2 categories: a “live” attenuated vaccine that contains a living but weakened form of the virus, or a “dead” vaccine that contains parts of the virus (but not an intact, live virus). In a patient with a normal immune system, either type of vaccine is cleared by the immune system, triggering the responses that lead to long-term immunity. Patients receiving immunosuppressive chemotherapy, however, may have altered responses.
As a general rule, patients receiving immunosuppressive chemotherapy should avoid live vaccines while undergoing treatment. This is due to a risk of the live, attenuated virus not being cleared by the immune system and potentially causing disease in the patient. Some examples of “live” vaccines include those against herpes zoster (Zostavax), the measles-mumps-rubella (MMR) vaccine, and yellow fever vaccines. Patients wishing to receive a live vaccine should discuss the timing of vaccine administration with their health care providers. Depending on the type of chemotherapy they received, patients may need to wait several months or more to allow their immune system to fully recover before receiving a live vaccine.
The “dead” vaccines do not pose the same risks to patients receiving immunosuppressive chemotherapy as they do not contain live viruses. However, the timing of these immunizations is also important. Patients who are immunosuppressed may have reduced or no response to vaccines administered, depending on their treatment, immunization timing, and other factors. These patients are therefore at risk of not developing the same long-term immunity after receiving a vaccine. Because of this, it is frequently recommended that these vaccines be administered prior to beginning immunosuppressive therapy. For patients who have already initiated chemotherapy (eg, the seasonal influenza vaccine), timing of the vaccine relative to chemotherapy doses should be discussed with the patients’ health care provider as many organizations have their own best practices.