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Background There is no uniform guideline for postchemotherapy vaccination of children with acute lymphoblastic leukemia (ALL). We evaluated waning immunity to 14 pneumococcal serotypes, pertussis toxin (PT), tetanus toxoid (TT) and varicella, and immunogenicity of postchemotherapy diphtheria, tetanus, pertussis, hepatitis B, polio, and Haemophilus influenzae type b (DTaP-IPV-Hib) and pneumococcal vaccination among previously vaccinated children treated for ALL. Methods This was a multicenter trial of children with ALL enrolled 4–12 months postchemotherapy completion. Exclusion criteria included: infant ALL, relapsed ALL, and stem cell transplant recipients. Immunocompetent children were recruited as controls. Postchemotherapy participants received DTaP-IPV-Hib and 13-valent pneumococcal conjugate vaccine (PCV13) concurrently, followed by 23-valent pneumococcal polysaccharide vaccine (PPV23) 2 months later. Serology was measured at baseline, 2 and 12 months postvaccination. Adverse events were captured via surveys. Results At enrollment, postchemotherapy participants (n = 74) were less likely than controls (n = 78) to be age-appropriately immunized with DTaP (41% vs 89%, P  < .001) and PCV (59% vs 79%, P  = .008). Geometric mean concentrations (GMCs) to TT, PT, PCV serotypes, and varicella were lower in postchemotherapy participants than controls after adjusting for previous vaccine doses (P  < .001). Two months postvaccination, GMCs to TT, PT, and PCV serotypes increased from baseline (P  < .001 for all antigens) and remained elevated at 12 months postvaccination. Antibody levels to PPV23 serotypes also increased postvaccination (P  < .001). No serious adverse events were reported. Conclusions Children treated for ALL had lower antibody levels than controls against pneumococcal serotypes, tetanus, pertussis, and varicella despite previous vaccination. Postchemotherapy vaccination with DTaP-IPV-Hib, PCV13, and PPV23 was immunogenic and well tolerated. Children with ALL would benefit from systematic revaccination postchemotherapy. Clinical Trials Registration NCT02447718. [ABSTRACT FROM AUTHOR]

Children with asplenia or hyposplenia are at risk of developing overwhelming sepsis. Health care providers caring for children with asplenia should ensure the best outcomes by using preventive strategies that focus on parent and patient education, immunization, antibiotic prophylaxis and aggressive management of suspected infection. The present position statement offers current guidance on each of these issues and replaces a previous CPS statement, 'Prevention and therapy of bacterial infections for children with asplenia or hyposplenia', published in 1999. [ABSTRACT FROM AUTHOR]