Following outbreaks of meningococcal disease in Quebec in 1991-1993 and 2000-2001, a government sponsored mass vaccination campaign was performed. In 2001-02, children between the ages of 2 months and 20 years were immunized with the meningococcal C-diphtheria conjugate vaccine (Menjugate™). We examined the response to vaccination of pediatric patients during or following maintenance chemotherapy for common childhood cancers as well as post-bone marrow transplantation.

This was an open label descriptive study of vaccine response to meningococcal C vaccine in a cohort of patients from the oncology clinic at the Montreal Children's Hospital. All patients had serum drawn prior to and one month following the vaccine to verify their serologic response. A positive response was defined as a four-fold increase in specific IgG from baseline. Complete blood count and T and B cell enumeration were obtained prior to vaccination.

Of 25 patients with ALL, 13 responded (12-275-fold increase) and 12 did not. Responders had a higher mean B cell count (0.262 × 10⁹/L) compared to non-responders (0.068 × 10⁹/L) (p<0.05). 11/12 of the non-responders and 4 of the responders were on maintenance chemotherapy. 2/5 patients post bone marrow transplant, 1/2 off therapy for solid tumors and 2/3 with lymphoma responded. The vaccine was well tolerated with no side effects noted.

In this mass vaccination campaign, meningococcal C conjugate vaccine proved safe but produced variable responses in children with common cancers. Proximity to chemotherapy and total B cell number may help predict likelihood of response.