Current recommendations for immunization in children with cancer: A narrative review

Pediatric cancers are one of the leading causes of death by disease among children world-wide, with non-cancer related morbidity and mortality burden due to vaccine preventable diseases being disproportionately high in developing countries. Besides standard-dose chemotherapy, groundbreaking therapeutic approaches - Monoclonal antibodies (MA), small molecule Janus kinase inhibitors (JKI), Chimeric antigen receptor T cell (CAR-T Cell) Therapy and Immune check point inhibitors (ICI) - have revolutionized oncology. This narrative review, collated until April 2026, elucidates key principles and enumerates relevant immunization strategies recommended by leading international bodies. The Infectious Diseases Society of America (IDSA) 2013 and Italian Association Paediatric Haematology Oncology (AIEOP) 2025 guidelines recommend ‘only routine immunization/continuation with boosters’ (resuming the schedule starting from the suspended dose) starting 3-6 months after chemotherapy completion. In contrast, the British ‘The Children and Young People's Cancer Association’ (CCLG) 2026 and Australian Immunization Handbook 2026 guidelines explicitly recommend revaccination with a single dose (even if the series had been completed prior to chemotherapy), commencing 3 months after chemotherapy completion. Live vaccines are contraindicated during cancer therapy. Live vaccines should be administered at least 4 weeks prior to commencing treatment with MA. Due to strong immunosuppressive effects on B-cells and hypogammaglobulinemia, for Blinantunomab [Anti-CD19], Inotuzumab-ozogamicin [Anti-CD22], Rituximab and Obinutuzumab [Anti-CD20], non-live vaccines are to be administered 6 months after stopping therapy, while live vaccines can be administered 12 months later. For Brentuximab-vedotin [Anti-CD30] and Gentuzumab-ozogamicina [Anti-CD33], non-live vaccines are to be administered 4 and 5 weeks respectively after stopping therapy, while live vaccines can be administered 3 months later. Live vaccines are recommended 2-4 weeks before or at least 3 months after JKI therapy ends. Live vaccines should be administered at least 4 weeks before commencing pre-CAR-T conditioning regimens. Non-live vaccines are to be administered at least 3 months after stopping CAR-T regimen. Live vaccines can be administered after 12 months provided there is evidence of immune restitution (CD19+ or CD20+ B cells > 0.2 × 109/L and CD4+ T cells > 0.2 × 109/L), evidence of detectable IgA, and at least 8 months since the last intravenous immunoglobulin dose. All live vaccines must be completed 4 weeks before the first ICI infusion, or administered at least 3 months after the final ICI dose. Routine sibling/contact vaccinations should continue except for oral poliomyelitis vaccine, which is contraindicated.