The results presented here are for the year 2011. In 2011, 275 laboratories participated, representing 344 short-stay healthcare facilities (73 university hospitals, 243 other public hospitals, 23 private hospitals, and 5 cancer centers). Nine laboratories from the French overseas departments also participated; their data are not included in this analysis. Following the modification of the case definition in 2009, which included cases detected by PCR, the incidence rates reported for the years 2009 through 2011 take into account cases detected by culture or by PCR. For the sake of comparability, the tables and figures presenting incidence rates and case numbers for years prior to 2009 are based solely on cases detected by culture. In 2011, the number of cases detected by PCR accounted for the following percentages of reported cases: 26% of reported cases due to N. meningitidis, 1% of reported cases due to L. monocytogenes, and less than 1% of reported cases due to H. influenzae, S. pneumoniae, S. pyogenes, and S. agalactiae.

Method for estimating national incidence

The coverage of the Epibac network

is calculated by dividing the number of medical admissions at facilities whose microbiology testing is performed by Epibac laboratories that participated for twelve months by the total number of medical admissions nationwide (see above). These data are provided by the Annual Survey of Public and Private Healthcare Facilities (SAE) conducted by the Directorate for Research, Studies, Evaluation, and Statistics (Drees).

The comprehensiveness of the network

corresponds to the completeness rate of case reporting within the Epibac network, i.e., by participating laboratories. It was estimated through several studies that measured underreporting of cases within the Epibac network for metropolitan France. The completeness rate of the data provided by participating laboratories was estimated to be between 74% and 94%, depending on the year and the bacteria studied. To ensure comparability with years for which the completeness rate was unknown, only data from the most recent year are adjusted for completeness when presented separately.

National-level estimates

Two estimates are produced:
The estimate of the number of cases adjusted for Epibac coverage allows for the analysis of annual trends in various conditions since 1991.
The estimate of the number of cases adjusted for coverage gaps and corrected for underreporting within the network is the one used for data from the current year.

The

Overall incidence and incidence by age group are calculated annually by dividing the estimated number of cases per disease by the number of people residing in metropolitan France and overseas territories for the year in question (source: INSEE**).

**Starting in 2006, the INSEE population projections used previously were replaced by localized population estimates (ELP). The comparative tables for previous years since 1991 have been adjusted