Abstract. 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.
Keywords. Children invasive - Pneumococcal infections - Vaccine
effectiveness - 7-valent pneumococcal conjugate vaccine
Abbreviations. HSS hospital surveillance system IPI
invasive pneumococcal infections KPT Kaiser Permanente Trial LSS
laboratory surveillance system 7-vPc 7-valent pneumococcal conjugate
vaccine
