Efficacy of 7-valent pneumococcal conjugate vaccination in Germany: An analysis using the indirect cohort method.

Efficacy of 7-valent pneumococcal conjugate vaccination has been shown in randomized controlled trials using 4 dose vaccination schedules in children under 2 years of age. A case-control study from the US showed considerable protection from IPD for reduced vaccination schedules and even some protection from only one dose. In Germany, delayed and incomplete vaccination is a major issue. We assessed efficacy of PCV7 using data on cases of IPD from active surveillance and applying the indirect cohort design proposed by Broome, comparing cases of IPD with a vaccine serotype with cases with a non-vaccine serotype. Efficacy of at least one dose of PCV7 was estimated to be 88.3% (95% CI: 64.0-96.6). Estimates of efficacy for one, two, and three doses in the first 7 months of life were 78.1% (3.4-96.1), 89.8% (20.6-100.0), and 94.6% (69.7-99.5) respectively. Our study adds to evidence of good protection from IPD by reduced vaccination schedules with PCV7, e.g. with two doses as primary series, in a setting where a high proportion of children receives vaccination delayed.