CTNI-24. NON-INFERIOR IMMUNE RESPONSES UPON COVID-19 BOOSTER AND SEASONAL INFLUENZA VACCINATION IN PRIMARY BRAIN TUMOR PATIENTS

Abstract BACKGROUND Patients with primary brain tumors are immunosuppressed, a condition further exacerbated by radiochemotherapy. Accordingly, a reduced immune response to vaccinations, including COVID-19 boosters, would be expected. However, data on vaccine and booster immunogenicity in this population are limited. METHODS Primary brain tumor patients eligible for a COVID-19 booster vaccine were screened between May and September 2023. Blood samples were collected before and 30 ± 2 days after receiving COVID-19 and seasonal influenza vaccines. Healthy individuals served as controls. RESULTS 37 primary brain tumor patients and 19 healthy controls were included. Median baseline anti-SARS-CoV-2 spike antibody were similar between groups. Following booster vaccination, median antibody titers increased to 14,228 BAU/ml (IQR: 12,326–16,913) in the brain tumor group and 13,266 BAU/ml (IQR: 9280–21,100; p = 0.7834) in the control group. Two patients were non-responders. No clinical or laboratory predictors of high post-booster titers (>15,000 BAU/ml) were identified. Influenza A and B immune responses were also comparable between groups. CONCLUSION Despite immunosuppression, patients with primary brain tumors show a strong immune response to the COVID-19 booster, indicating effective immunogenicity.