Pneumococcal conjugate vaccine administration during therapy for pediatric leukemia.

Abstract

Pediatric leukemia patients are at high risk of invasive pneumococcal disease. The study aim was to determine the antibody response to a 10-valent pneumococcal conjugate vaccine (PCV10) administered during chemotherapy. An open-label study in pediatric leukemia patients: Group 1 had completed a primary 7-valent (PCV7) course and received a single PCV10 dose. Group 2 were PCV immunization naïve and received 3 doses of PCV10, administered 2 months apart. Serum samples were taken at baseline and 1 month post each PCV10 dose. Antipneumococcal serotype-specific IgG to 10 serotypes were measured by enzyme-linked immunosorbent assay and the functional response to 4 serotypes (1, 6B, 19F and 23F) was measured using opsonophagocytic assays. Thirty-nine participants were recruited between May 2010 and January 2011; group 1 (n = 27) and group 2 (n = 12). The diagnosis was acute lymphoblastic leukemia (38) and acute myeloid leukemia (1). Median age was 6.2 years (1.7-17.2 years) with 62% male. The median time from diagnosis to baseline serology was 7.4 months (1.6-36.8 months). At baseline, protective geometric mean concentration above the threshold (>0.35 μg/mL) ranged from 5.3% (serotype 4) to 71% (serotype 19F). More than 60% of participants in both groups were above threshold postimmunization for 7 of the 10 PCV serotypes. Opsonophagocytic assay correlated with enzyme-linked immunosorbent assay for 3 of the 4 serotypes and r ranged from 0.51 to 0.84. An injection-site reaction was reported in 73% (27/37). It is safe to administer PCV10 vaccine during therapy for pediatric leukemia. It provided a satisfactory serum immune response for the majority of vaccine serotypes.