Immune response to conjugated meningococcal C vaccine in pediatric oncology patients

Background Following outbreaks of meningococcal disease in Quebec in 1991–1993 and 2000–2001, a mass vaccination campaign was performed. In 2001–2002, children aged 2 months to 20 years were immunized with the Meningococcal CRM197 vaccine (Menjugate™). We examined the response of pediatric oncology patients during or following maintenance chemotherapy and post‐bone‐marrow transplantation to Meningococcal C vaccine. Procedure This was an open label descriptive study of a cohort of patients from the oncology clinic at the Montreal Children's Hospital. A positive vaccine response was defined as a fourfold increase in specific IgG from baseline and a bactericidal assay using human complement (hBCA) titer >1:4. Results Of the 25 patients with ALL, 13 had a serologic response (average 60‐fold increase). The serologic responders had a higher mean B cell count (0.262) compared to non‐responders 0.068 × 10.9/L [ t (23) = 2.843 ( P  < 0.05)]. Eleven of the 12 non‐responders and 4 of the responders were on maintenance chemotherapy. In addition, two of the five patients post‐bone‐marrow transplant, responded. Fifteen of the 34 patients (44%) had an adequate hBCA response (mean titer 61). The group included 14/18 serologic responders with hBCA response ( P  < 0.001) and 16/17 non‐serologic responders with no hBCA response ( P  < 0.001). Conclusions Meningococcal C‐conjugate vaccine produced variable responses in children with common cancers. Proximity to chemotherapy and total B cell number may help predict likelihood of response. Pediatr Blood Cancer 2007;49:918–923. © 2007 Wiley‐Liss, Inc.