Authors’ response: Meningococcal vaccine antigen diversity in global databases Brehony, Carina and Hill, Dorothea M. and Lucidarme, Jay and Borrow, Ray and Maiden, Martin C., Eurosurveillance, 21, 30192 (2016), https://doi.org/10.2807/1560-7917.ES.2016.21.15.30192