Nainani V, et al. - This retrospective review was planned to determine whether the introduction of the capsular group B meningococcal vaccine (4CMenB) in the UK has increased presentations of infants to emergency departments with adverse events following immunisation (AEFI). Following 4CMenB immunisation, researchers identified an increase in emergency department attendances, investigations and antibiotic use for AEFIs, that seemed to influence the cost-effectiveness of the 4CMenB immunisation campaign.