IMMUNIZATION OF PEDIATRIC ONCOLOGY PATIENTS WITH HAEMOPHILUS INFLUFNZAE TYPE B (HIB) POLYSACCHARIDE VACCINE

Abstract

Although at increased risk for Hib infection, there are limited data concerning safety and immunogenicity of Hib polysaccharide vaccine in children with malignancies. 43 children with malignancies (19 with acute lymphoblastic leukemia, ALL, age 3-20y;15 with Hodgkins Disease, HD, s/p splenectomy, age 16-22y; 9 with other malignancies, age 2-19y) received 25mg vaccine SQ (b CAPSA-I, Praxis Biologies). At time of vaccination, patients were not receiving induction chemotherapy and were not neutropenic. The vaccine was extremely well tolerated with no side effects in anyof 43 children. Prevacclnation anti-PRP antibody (by RIA) was<0.15 meg/ml in 8 of 19 with ALL (geo mean 0.25mcg/ml), 2 of 15 with HD (geo mean 0.70) and 2 of 10 with other malignancy (geo mean 0.58). Inadequate response (Imo postvaccination Ab level of< 1mcg/ml) was found in 10 of 18 with ALL (geo mean 1.1mcg/ml, 4 of 19 had< 0.15mcg/ml), 5 of 11 with HD (geo mean 2.1) and 3 of 8 with other malignancies (geo mean 1.71). There was no significant correlation between postvaccination Ab level and age, sex, serum IgG, IgM IgA, absolute lymphocyte or granulocyte count for any of the groups. There was a positive correlation between log pre-and log postvaccination Ab level for all 3 groups (p<.05). For ALL patients, there was a significant negative correlation between no. months of chemotherapy and log post-immunization Ab (p<.01). Thus, immunization with Hib polysaccharide vaccine cannot be relied upon to protect these patients from Hib disease.