Evaluation of Immune Response after Vaccinations Post-chemotherapy in Childhood Cancer Survivors / 임상소아혈액종양

ABSTRACT

BACKGROUND: Survivors of childhood cancers are recommended to receive revaccinations after chemotherapy, although the universally recommended vaccination schedule for such children has not been established. We evaluated immune response following post-chemotherapy vaccinations in childhood cancer survivors. METHODS: The study included 59 patients who survived at least 5 years after completion of chemotherapy without evidence of recurrence. The patients received hepatitis-B virus (HBV) and measles, mumps, and rubella (MMR) vaccines 1 year after finishing chemotherapy according to our institutional protocol. Immune response to HBV and MMR vaccines was measured and seropositivity and factors hindering immune response to HBV and MMR vaccines were analyzed. RESULTS: The seropositivity for HBV was 88%; with a higher rate in patients with non-hematologic malignancies (100%, 18/18) than those with hematologic malignancies (78.3%, 18/23) (P=0.05) and reciprocally associated with the duration of chemotherapy (P=0.0043). The seropositivity for MMR viruses was 61%, 37% and 83% respectively, showing significantly lower response to mumps and was not different between hematologic malignancy group and non-hematologic malignancy group. Unlike HBV, the duration of chemotherapy did not affect seropositivity for MMR viruses. Ten children who failed to be immune to any of the MMR viruses received booster vaccination which resulted in seropositivity of 60% (3/5), 56% (4/9), 100% (2/2) respectively. CONCLUSION: Longer duration of chemotherapy and underlying hematologic malignancies were adversely associated with achieving immune response to HBV vaccine, but not to MMR vaccine. Our results also underline the need for booster vaccinations in non-responders to vaccinations post-chemotherapy.