Distribution of serotypes 6A, 6B, and 6C among Streptococcus pneumoniae isolates recovered from invasive pneumococcal disease (meningitis and bacteremia, n = 12,345) according to age group, from 2002 to 2011.

Introduction of PCV7 in France, March 2002, for children at high risk for IPD; Generalization of PCV7 for children <2 years in 2006; Introduction of PCV13 in France, June 2010.

*Significant trend over the 5 periods, calculation was performed by the extended Mantel-Haenszel Chi square test for linear trend.

°Serotype conventionally determined as 6A that could not be further tested for serotype 6C.

NA, Not applicable; NS, not significant.