098 - Immunity to Pneumococcus in Childhood Cancer Survivors

Publication Number: 98.5366

Emily K. Cathey, The Barbara Bush Children's Hospital at Maine Medical Center, PORTLAND, ME, United States; Ivan D. Cardona, The Barbara Bush Children's Hospital at Maine Medical Center, Portland, ME, United States; Edmund H. Sears, Tufts University School of Medicine, South Portland, ME, United States; Susan A. Speckhart, MaineHealth, Falmouth, ME, United States

Background: Long-term childhood cancer survivors (CCS) are at increased risk for life-threatening pneumonia.12 Although the specific types of pneumonia affecting CCS have not been described, pneumococcal pneumonia is responsible for 10% to 30% of all community-acquired pneumonia in adults and is the most common cause of bacterial pneumonia in children.3 Children are routinely immunized against pneumococcus at age < 5 years, however previous findings have indicated that CCS often exhibit low levels of pneumococcal titers within one year post-treatment.4 However, it is unknown if long-term CCS re-acquire protective titers against pneumococcus.

Objective: Our study aimed to evaluate whether long-term CCS have titers to pneumococcal serotypes that confer protections against pneumococcal disease.

Design/Methods: This is a retrospective chart review of pediatric cancer survivors seen at the MaineHealth Cancer Survivorship Program from January 1, 2021 to February 29, 2024. All patients previously received chemotherapy. Twelve pneumococcal serotypes (1,3,4,8,9N,14,19,23,26,51,56) were evaluated based on the available laboratory testing panel. Immunity to non-invasive pneumococcus was defined as titers greater than 1.3 ug/ml. Stratification of these titers was based on sex, cancer diagnosis category, age, time since cancer diagnosis, time since completion of treatment, and verification of vaccination records. Descriptive statistics were calculated.

Results: We identified 71 CCS who were treated with chemotherapy and had pneumococcal titers assessed prior to booster immunization. On average, CCS were immune to fewer than 2 of the 12 serotypes tested. Only 4 out of 71 (6%) had immunity to at least 6 of the titers tested. There were no significant differences in immunity based on sex, age, cancer diagnosis, age at diagnosis, time since diagnosis or end of treatment, or if administration of primary pneumococcal vaccination series was verified. (Table 1) The findings indicate that the overwhelming majority of pediatric cancer survivors in this population (94.4%) do not have protective titers against sinopulmonary pneumococcal infections, and immunity did not appear to increase further out from diagnosis and treatment.

Conclusion(s): CCS fail to acquire protective titers to pneumococcal sinopulmonary disease. Lack of immunity may contribute to the increased incidence of sinopulmonary infections in CCS. Pneumococcal vaccination should be considered following the completion of chemotherapy in all CCS who receive chemotherapy.

Table 1: Pneumococcal Immunity in Childhood Cancer Survivors
Average number of patients with titers > 1.3 ug/dL and percentage of patients with positive titer, broken down by serotypes.