Abstract
BACKGROUND: Chemotherapy, a cornerstone treatment for Acute Lymphoblastic Leukemia (ALL), can compromise immune function, leading to impaired immune memory function and diminished responses to revaccination. This systematic review and meta-analysis sought to evaluate the impact of chemotherapy on the immunogenicity of prior vaccinations and subsequent revaccination responses in children with ALL. METHODS: A comprehensive search was conducted through PubMed, Embase, Web of Science, and Medline. Search time was 9 January 2025. R 4.4.2 was employed for data analysis. RESULTS: A total of 29 relevant studies were identified, with 8 undergoing meta-analysis. The pooled antibody seropositive rates (SPR) for vaccines against Hepatitis B Virus (HBV), Hepatitis A Virus (HAV), diphtheria, tetanus, pertussis, measles, mumps, rubella, varicella, and Pneumococcal Conjugate Vaccine (PCV) demonstrated a statistically significant decline after chemotherapy in ALL patients (p < 0.0001). Subgroup analysis further revealed marked and heterogeneous declines in SPR after chemotherapy, with the magnitude of reduction varying significantly across vaccines-tetanus, HBV, HAV, measles, mumps, and rubella (Subgroup differences, p = 0.0037). CONCLUSIONS: This review provides an updated assessment of this critical topic, representing the first meta-analysis specifically focused on the effects of chemotherapy on different vaccines' immunogenicity in children with ALL.