Immunization in cancer patients: where we stand

An increasing proportion of cancer patients benefit from new treatment strategies. However, infection remains a main cause of morbidity and mortality, either due to the underlying diseases, to treatment, or both. Although most opportunistic infections are sofar not routinely preventable by vaccines, community infections such as invasive pneumococcal disease and influenza may be avoided by vaccines in many instances. The immune response of cancer patients to vaccines is almost constantly depressed when compared to the one of healthy individuals of the same age range. However, they may, in many cases, reach seroprotection. This article addresses the rationale to develop and implement immunization programs in cancer patients, including patients with hematologic malignancies and recipients of stem cell transplantation, and the main specificities of this patient population regarding vaccines, and the potential approaches to improve the immune response. The Infectious Diseases Society of America has recently published guidelines for vaccination of the immunocompromised hosts. Although many questions remain to be clarified, oncologists and hematologists should be encouraged to implement these guidelines in their therapeutic programs and to develop prospective studies covering unsolved issues.