Meningococcal disease can affect all age groups, but the rates of disease are highest in children under five years of age, with the peak in babies under one year of age. There's a second peak in cases in young people aged between 15 and 19. The disease tends to strike in winter.The Meningitis C vaccine has an excellent safety record. The most common reactions tend to be minor and very temporary. They include swelling, redness and pain around the injection site.