Epidemiological and strain characteristics of invasive meningococcal disease prior to, during and after COVID-19 pandemic restrictions in England

Abstract

In 2020, COVID-19 pandemic restrictions led to a major suppression of meningococcal disease in England. Here we describe the epidemiology of invasive meningococcal disease in the three years prior to the COVID-19 pandemic, and the three years immediately after the introduction of restrictions. The UK Health Security Agency conducts national meningococcal disease surveillance in England consisting of laboratory-based case confirmation with strain characterisation by culture and/or molecular detection, as well as clinical follow-up of all cases. In the pre-pandemic period, 554-742 IMD cases were laboratory-confirmed per year. MenB caused 57.2% of cases, followed by MenW (22.7%), MenY (10.6%) and MenC (7.7%). The introduction of restrictions in late March 2020 led to a 73% reduction in IMD. After the removal of restrictions in 2021, a resurgence in MenB was observed, primarily in teenagers and young adults. During the following winter period (2022/23), MenB disease increased to the highest level since 2012 with cases rising across multiple age groups, however, cases in young children eligible for MenB vaccination remained lower than prior to the pandemic. MenACWY cases remained very low throughout the pandemic period. Once pandemic restrictions in England were removed, MenB quickly rebounded- initially driven by a resurgence in teenagers/young adults, but later among other age groups. MenACWY cases remain very low due to the protection afforded by the adolescent MenACWY conjugate vaccine programme.