Immunisation in children with cancer

Immunosuppression of varying degree is present in children with cancer. This can range from mild to severe. Cancer itself, particularly leukaemia and lymphoma, can cause suppression of cellular and humoral immune function. However, cytotoxic antineoplastic therapy is the main contributor. Immune alteration is reflected by decreases in neutrophils, lymphocytes, immunoglobulin levels, and specific antibodies against previous vaccinations and infections. Immune recovery post-treatment occurs in a differential manner, with innate immune function recovering before adaptive immune function, and with B-cell function recovering faster than T-cell function. As a result of these changes children with cancer, and particularly those who are also haematopoietic stem cell transplant (HSCT) recipients, have an acquired immune deficiency, and are at increased risk of significant morbidity and mortality from infections. It is therefore important to ensure that such children are maximally protected against vaccine-preventable diseases. This can be achieved by optimising the vaccination strategy in children during immunosuppressive cancer treatment and after completion of treatment. Vaccination should be routine practice for all children treated for cancer. The vaccination strategy should not only include the patient, but also the household members and healthcare contacts of the patient.