Assessment of Antibody Levels and Vaccine-Induced Serological Responses
after completion of cancer treatment in Pediatric Patients: A Six-Year
Experience in Turkey on HAV, HBV, VZV, and MMR Vaccinations
Abstract
Objective: Cancer treatment in children leads to failure to
complete the childhood vaccination program and weakening or loss of
vaccine-acquired immunity. Post-treatment vaccine responses of children
receiving cancer treatment vary. In this study, we aimed to investigate
serum antibody status, and vaccine responses in children after cancer
treatment. Methods: Pediatric patients who were admitted to
Hacettepe University Hospitals between January 1, 2015, and December 31,
2020, who received chemotherapy for lymphoma and solid organ tumors, and
whose diseases were in remission were included in the study. Vaccines
administered after cancer treatment, hepatitis A (HAV), hepatitis B
(HBV), varicella zoster (VZV), measles-mumps-rubella (MMR) serum
antibody levels, and changes in vaccine responses after treatment were
retrospectively investigated. Results: The study included 533
patients. After treatment, measles, HAV, rubella, HBV, VZV, and mumps,
seronegativity were found in 83.5%, 64%, 60.1%48,5%, 43.3%, and
28%of the patients, respectively. Post-treatment rates of antibody loss
in descending order were measles (47.1%), HAV (31.9%), HBV (31.4%),
mumps (28.6%), VZV (21.7%), and rubella (11.4%). Seroconversion rates
to one dose of vaccines in descending order, were (83.6%), rubella
(82.9%), HBV (81.4%), VZV (63.5%), mumps (45.4%), and measles
(33.3%). Seroconversion rates to two doses of the same vaccines, in
descending order, were: HAV (98.8%), VZV (84.6%), rubella (80%), HBV
(80%), measles (32.2%), and mumps (36.2%) Conclusion:
Serologic vaccine responses of patients after treatment were lower than
expected even with repeated doses. As these patients may require
intermittent serologic evaluations and repeated vaccinations according
to their risk status, we have planned longer-term follow-ups of them.