Corrigendum to “Persistence of bactericidal antibodies following booster vaccination with 4CMenB at 12, 18 or 24 months and immunogenicity of a fifth dose administered at 4 years of age-a phase 3 extension to a randomised controlled trial” (Vaccine (2017) 35(2) (395–402) (S0264410X16310404) (10.1016/j.vaccine.2016.11.009))