Does the 23-valent pneumococcal vaccine protect cochlear implant recipients?

The incidence of meningitis is increased in cochlear implant (CI) recipients. Besides malformations, immunological deficiencies are predisposing factors. Therefore, the immunological background of CI recipients and the immunogenicity of the recommended 23-valent pneumococcal polysaccharide vaccine (PPV-23) were investigated.

Prospective study in a tertiary care referral center.

One hundred twenty CI recipients who were at least 5 years of age were vaccinated with PPV-23. Levels of immunoglobulins G, A, and M (IgG, IgA, and IgM, respectively) and IgG subclasses IgG1-IgG4 before vaccination and serum concentrations of antibodies against seven pneumococcal serotypes before and 4 weeks after vaccination were determined. The cohort was subdivided by patient age into groups A1 (5-8 y), A2 (8-12 y), and A3 (>12 y).

Geometric mean concentrations of pneumococcal antibodies before vaccination were remarkably low in all three groups, emphasizing the importance of vaccination in this risk group. All groups showed a statistically significant increase in geometric mean concentrations after immunization. For group A1 compared with groups A2 and A3, response was limited, especially for serotypes 6B (geometric mean concentration, 1.71 microg/mL; P = .0007), 23F (geometric mean concentration, 2.28 microg/mL; P = .04), and 14 (geometric mean concentration, 3.98 microg/mL; P = .0004). The percentages of patients reaching the presumed protective threshold of at least 1 microg/mL pneumococcal antibody concentration were at least 71.1% in group A1, 93.8% in group A2, and 90.5% in group A3. This raises the question of whether PPV-23 evokes satisfying seroprotection in CI recipients younger than 8 years of age.

With regard to the increased risk for bacterial meningitis, the authors recommend priming CI recipients younger than 8 years of age with pneumococcal conjugate vaccine followed by a PPV-23 booster.