Pneumococcal conjugate vaccine primes for antibody responses to polysaccharide pneumococcal vaccine after treatment of Hodgkins disease

Thirty-nine previously treated Hodgkin's disease (HD) patients were immunized with 7-valent pneumococcalconjugate vaccine (7-0MPC) followed by one dose of 23-valent polysaccharidepneu-mococcal vaccine (23-PS). To determine the priming effect of 7-0MPC vaccine, their antibody responses to six serotypes contained in both vaccines were compared to those of 57 HD patients who received 23-PS vaccine only. The geometricmean antibody concentrations after immunization with 23-PS vaccine were significantly higher for five of the six measured serotypes in HD patients primed with 7-0MPC vaccine compared with responses in HD patients who received 23-PSvaccine only. The mean of the six antibody concentrations was significantlyhigher for the primed group at 12.5 ILglmL and 7.76 ILglmL, respectively (P =.015). Priming with a conjugate vaccine should be considered as a strategy to protect high-risk adults. Patients with Hodgkin's disease (HD) are at increased risk for serious bacterial infections with encapsulated organisms such as Streptococcus pneumoniae and Haemophilus infiuenzae type b (Hib). Major risk factors include splenectomy and inten-sive therapy for HD; this risk persists for years despite success-ful treatment of the underlying hematologic disease [1-3]. Ret-rospective studies in children and adults with HD report an incidence of serious bacterial infection ranging from 2 % to 21%, with S.pneumoniae being the leading cause ofmeningitis, bacteremia, and pneumonia. Although immunization before ini-tiation of treatment may lower the risk, vaccine failures occur [4]. Furthermore, after treatment of HD, poor responses to polysaccharide vaccines have been documented [5, 6]. Recently, more immunogenic polysaccharide conjugate vac-cines have been produced by linking polysaccharide to protein carrier molecules. We previously demonstrated that Hib conju