In Normandy and Picardy, the Cire Normandie and the Cire Nord conducted a survey in the spring of 2013 in Seine-Maritime and the Somme to estimate vaccination coverage with the MenBvac® vaccine following the vaccination campaign against invasive meningococcal disease (IMD) B, which had been underway in these two departments since 2006. This was a mail survey using a standardized questionnaire that included information on several vaccine valences, including MenBvac®. The results obtained from the mail survey were compared with those derived from computerized data collected during the campaign in a database using the Gestimes® software, which recorded the vaccination status of all eligible individuals. The response rate for the mail survey was 33.6% (2,453 out of 7,303 letters delivered). The concordance coefficient between the mail survey and the Gestimes® database was satisfactory (0.75), and the difference between the mail survey and the Gestimes® results was deemed sufficiently small (<5%) and explainable to validate the use of Gestimes® data for the entire sample. Analysis of the full sample yielded results 15 to 20% lower than those from the analysis of postal survey respondents. This means that individuals who responded to the postal survey were more likely to be vaccinated than those who did not respond. Several factors suggest that the results for the full sample better reflect reality than the results among postal survey respondents, notably the comparison of vaccination coverage for valences other than MenBvac® with regional data sources. Consequently, the mail survey as conducted in Seine-Maritime and the Somme could not provide a usable estimate of vaccination coverage. However, this survey validated the use of a computerized database (Gestimes®) containing the vaccination status of individuals tracked through a one-time extraction of data from the Health Insurance system. Analysis of the entire sample using Gestimes® data yielded the following results: 66.3% for primary vaccination (3 doses of vaccine) and 43.9% for a complete 4-dose regimen. (R.A.)