Epidemiological trends in viral meningitis in England: Prospective national surveillance, 2013-2023

Background: In the conjugate vaccine era, viruses are the most common cause of meningitis. Here, we evaluated epidemiological trends in laboratory-confirmed viral meningitis across all age-groups over an 11-year period in England. Methods: In England, hospital laboratories routinely report laboratory-confirmed infections electronically to the UK Health Security Agency. Records of positive viral detections in cerebrospinal fluid during 2013-2023 were extracted. Incidence rates with confidence intervals were calculated using mid-year resident population estimates. Results: There were 22,114 laboratory-confirmed viral meningitis cases, including 15,299 cases during 2013-19 (pre COVID-19), with a gradual increase in incidence from 3.5/100,00 (95%CI, 3.3-3.6) to 3.9/100,000 (95%CI, 3.6-4.1). During 2020-21 when pandemic restrictions were in place, there were 2,061 cases (1.8/100,000; 1.7 - 1.9), which increased to 4,754 (4.2/100,000; 4.0-4.3) during 2022-23 (post pandemic restrictions). Infants aged <3 months accounted for 39.4% (8,702/22,048) of all cases, with a stable incidence 2013-19 (504/100,000, 95%CI: 491-517), followed by a significant decline during 2020-21 (204/100,000; 188-221) and then an increase during 2022-23 (780/100,000; 749-812), with enteroviruses being the commonest cause (84.9%, 7387/8,702; 424.74/100,000; 95%CI, 415.12-434.51), followed by parechoviruses (9.1%, 792/8702; 45.54/100,000; 95%CI, 42.42-48.82) and herpes simplex virus (4.4%, 380/8702; 21.85/100,000; 95%CI, 19.71-24.16). Pandemic restrictions were associated with significant declines in the incidence of enterovirus (77.7%) and parechoviruses (64% lower), with rebounds after societal restrictions lifted. Conclusions: Rates of viral meningitis have returned to pre-pandemic levels since societal restrictions were lifted. The highest incidence of viral meningitis remains in infants aged <3 months and most commonly due to enteroviral infection. (c) 2024 The Author(s). Published by Elsevier Ltd on behalf of The British Infection Association. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).