Real-world vaccination status of children with hematologic tumors before and after chemotherapy

Background There is a high incidence and mortality rate in children with hematologic tumors (CHT), who are more prone to various infectious diseases. This study aims to clarify the real-world National Immunization Program (NIP) vaccination status of CHT before and after chemotherapy. Methods Medical records, NIP vaccination data, and the Adverse Event Following Immunization (AEFI) of CHT who were admitted to the Children's Hospital, Zhejiang University School of Medicine, from 1 January 2011 to 1 December 2021 were completely collected. Results A total of 2,874 CHT were included, and 1975 (68.7%) had vaccination records. Among the enrolled patients, the vaccination rate of all NIP vaccines was lower than 90% before diagnosis. Only 24.29% of CHT (410/1688) resumed vaccination after chemotherapy, and 69.02% (283/410) resumed vaccination more than 12 months after chemotherapy. No uncommon or serious side effects were reported. Conclusion The vaccination rate of CHT after chemotherapy was lower than that before the disease was diagnosed. It is necessary to provide more evidence-based support and formulate specific regimens to perfect the vaccination procedure after chemotherapy so as to improve the quality of life of CHT.