Prediction of the potential benefit of different pneumococcal conjugate vaccines on invasive pneumococcal disease in German children

Background.

In the US a pneumococcal conjugate vaccination program with a 7-valent conjugate vaccine was successfully implemented in 2000. How much invasive pneumococcal disease can potentially be prevented by the 7-valent (or 11-valent) vaccine in Europe?

Methods.

Prospective, active surveillance of invasive pneumococcal disease in German children age <16 years was performed between 1997 and 2000. Age- and disease-specific coverage and incidence rates were assessed in children old enough to benefit from complete vaccination to estimate the annual number of cases potentially preventable.

Results.

A total of 1,743 cases were reported; 667 isolates were serotyped. Coverage of 7-valent (11-valent) conjugate vaccines in children age 6 months and older was age- and diagnosis-dependent, ranging from 10.5% (15.8%) to 78.3% (82.6%) for meningitis and from 13.6% (68.2%) to 75.0% (89.3%) for nonmeningitis invasive pneumococcal disease cases. Of an estimated annual number of 176 children with pneumococcal meningitis age 6 months or older, 112 (122) cases had serotypes included in the 7-valent (11-valent) conjugate vaccine compared with 181 (254) of 324 nonmeningitis invasive pneumococcal disease cases, with 37 of the 73 cases covered by the 11-valent vaccine only in children older than 5 years. Regarding meningitis in this age group the potential benefit was equally poor for both the 7-valent (12 of 37 cases) and the 11-valent vaccine (15 of 37 cases).

Conclusion.

Coverage of the 7- and 11-valent conjugate vaccines depends markedly on age and disease. The additional potential benefit of the 11-valent compared with the 7-valent vaccine for pneumococcal meningitis was marginal.