ABSTRACT
Introduction: Acute myocarditis has been reported in patients infected with COVID-19 in case series and imaging-based studies. We sought to assess this link by evaluating trends in hospital admissions due to acute myocarditis and COVID-19 on a national level during the pandemic. Methods: Data on all NHS England hospital admissions with a primary or secondary diagnosis of acute myocarditis were acquired and curated from the NHS Digital hospital episode statistics dataset from 2019-2020. COVID-19 data was obtained from the UK government daily statistics. Rolling averages over 28-day periods are presented. Results: Across all ages, there were 1,894 hospital admissions due to myocarditis in 2019 compared with 1,610 in 2020 (15% reduction). During the first national lockdown (23rdMar-19thJun 2020), myocarditis admissions were 32% lower than the same period in 2019. During the second lockdown (5thNov-2ndDec), myocarditis admissions were 9% greater than in 2019, although this increase was not sustained throughout December despite the subsequent surge in COVID-19 admissions. In general, patients admitted in 2020, compared to 2019, were older (median age 46 years, interquartile range 28-61 vs 41 years, IQR 26-58;p<0.001), but sex (66% men), ethnicity (39% non-Caucasian, 9% unknown) and duration of hospital admission (median 2 days;IQR 1-4) were similar for both years. Discussion: As COVID-19 admissions peaked in early 2020, there was a sharp decline in myocarditis admissions, probably attributed to profound disruptions in healthcare provision, but possibly due to reduced transmission of other viruses during lockdown. Whilst myocarditis admissions increased during the second lockdown, there was no clear association between COVID19 and myocarditis admission numbers. Further research may identify delayed presentations or sequelae of myocarditis, particularly following the larger COVID-19 peak in January 2021, as well as the impact of the vaccination programme.