Depending upon the prevalence of serogroup A meningococcal carriage in the 2011 rainy season survey conducted in Chad, a decision will be made as to whether or not to proceed with two post-vaccination surveys as indicated in the original protocol for Mali and Niger. Vaccination of the whole of Chad with MenAfriVac™ will commence in the last quarter of 2011 and the whole country is likely to be covered by early 2012.