Administration of Protein‐Conjugate Pneumococcal Vaccine to Patients Who Have Invasive Disease after Splenectomy Despite Their Having Received 23‐Valent Pneumococcal Polysaccharide Vaccine

Abstract

Patients who undergo splenectomy are at greatly increased risk for overwhelming pneumococcal bacteremia and death. Twenty-three-valent pneumococcal polysaccharide vaccine (PPV-23), which contains capsular polysaccharides (PSs) from 23 common serotypes of Streptococcus pneumoniae, is strongly recommended for such patients. The capacity to respond to PPV-23 by producing immunoglobulin (Ig) G is genetically regulated. Some proportion of adults do not respond and, despite postsplenectomy administration of PPV-23, may remain susceptible to recurrent pneumococcal sepsis. Here, we describe 2 patients who had recurring pneumococcal bacteremia after undergoing splenectomy despite having received numerous doses of PPV-23. Heptavalent protein-conjugate pneumococcal vaccine (PCPV-7) was then administered, and it induced high levels of IgG to all 7 PSs; in one of the patients, functional activity against 5 of the 7 PSs was demonstrable, both in vitro and in vivo. Recurrent pneumococcal bacteremia in patients who have undergone splenectomy may indicate a genetically regulated failure to respond to PPV-23; PCPV-7 may stimulate production of IgG to PSs in such patients.