Distribution of serotypes 6A, 6B and 6C among Streptococcus pneumoniae isolates recovered from nasopharyngeal carriage in children aged 6–23 months, from 2002 to 2011.

Introduction of PCV7 in France, March 2002, for children at high risk for IPD; Generalization of PCV7 for children *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.