A 7-valent pneumococcal conjugate (7-vPc) vaccine was shown to be highly effective in California preventing 89.1% of all invasive pneumococcal infections (IPI) regardless of serotype. There is concern whether a similar effectiveness will be attained in Germany where 52% of all IPI in children <16 years were caused by the serotypes in the vaccine. The study was based on prospective, active surveillance of IPI in German children aged <16 years during 1997 to 2000. Coverage by the 7-vPc vaccine (with and without 6A) in unvaccinated children in the Kaiser Permanente Trial (KPT) was compared to the coverage in German children in the same age period as in the KPT. The proportion of potentially preventable cases was estimated both for unvaccinated children in the KPT and for Germany by multiplication of the coverage rates with the vaccine efficacy estimate from the KPT (intention to treat analysis). Successful serotyping could be attained for 38.3% of the 1,743 German IPI cases. In the age period from 7 to 43 months concerned in the KPT, the proportion of cases with serotypes covered by the 7-vPc vaccine (+6A) was 91% (95% CI 80%-97%) in the unvaccinated children in the KPT compared to 76% (95% CI 71%-80%) in Germany. The respective estimates for the number of potentially preventable IPI cases were 85% (95% CI 75%-91%) in the KPT compared to 71% (95% CI 67%-75%) in Germany.
Conclusion: Age specific serotype coverage rates have to be considered for extrapolation of the Kaiser Permanente Trial to the German situation. Although 14% lower than in the Kaiser Permanente Trial, 71% of potentially preventable cases of invasive pneumococcal infection still predict an excellent effectiveness for the 7-valent pneumococcal conjugate vaccine in Germany.