Association Between COVID-19 and Myocarditis Using Hospital-Based Administrative Data — United States, March 2020–January 2021

Abstract

On August 31, 2021, this report was posted as an MMWR Early Release on the MMWR website (https://www.cdc.gov/mmwr).Viral infections are a common cause of myocarditis, an inflammation of the heart muscle (myocardium) that can result in hospitalization, heart failure, and sudden death (1). Emerging data suggest an association between COVID-19 and myocarditis (2-5). CDC assessed this association using a large, U.S. hospital-based administrative database of health care encounters from >900 hospitals. Myocarditis inpatient encounters were 42.3% higher in 2020 than in 2019. During March 2020-January 2021, the period that coincided with the COVID-19 pandemic, the risk for myocarditis was 0.146% among patients diagnosed with COVID-19 during an inpatient or hospital-based outpatient encounter and 0.009% among patients who were not diagnosed with COVID-19. After adjusting for patient and hospital characteristics, patients with COVID-19 during March 2020-January 2021 had, on average, 15.7 times the risk for myocarditis compared with those without COVID-19 (95% confidence interval [CI] = 14.1-17.2); by age, risk ratios ranged from approximately 7.0 for patients aged 16-39 years to >30.0 for patients aged <16 years or ≥75 years. Overall, myocarditis was uncommon among persons with and without COVID-19; however, COVID-19 was significantly associated with an increased risk for myocarditis, with risk varying by age group. These findings underscore the importance of implementing evidence-based COVID-19 prevention strategies, including vaccination, to reduce the public health impact of COVID-19 and its associated complications.Data for this study were obtained from the Premier Healthcare Database Special COVID-19 Release (PHD-SR), a large hospital-based administrative database. † The monthly * These authors contributed equally to this report. † PHD-SR, formerly known as the PHD COVID-19 Database, is a large U.S. hospital-based all-payer database that includes inpatient and hospital-based outpatient (e.g., emergency department or clinic) health care encounters from >900 geographically diverse, nonprofit, nongovernmental, community, and teaching hospitals and health systems from rural and urban areas. PHD-SR represents approximately 20% of inpatient admissions in the United States.

Immune Response in Myocardial Injury: In Situ Hybridization and Immunohistochemistry Techniques for SARS-CoV-2 Detection in COVID-19 Autopsies

“…Patients with myocarditis were more commonly male (59.3 versus 41.7%). Despite the limitations, the observed myocardial lesions in our cohort may still be concordant with other studies ( Boehmer et al, 2021 ).…”

Should children be vaccinated against COVID-19?

“…36 Another study reported an adjusted risk ratio for myocarditis from patients with COVID-19 compared with patients without COVID-19 of 36.8 in children less than 16 years of age and 7.4 in adolescents 16-24 years of age. 37 A third study reported an 8.2-fold increase in myocarditis admissions during the pandemic, but no cases among the 1371 children and adolescents less than 18 years of age. 38 Information on the long-term outcome of myocarditis resulting from SARS-CoV-2 infection (e.g., progression to fibrosis) is currently lacking.…”

COVID-19 Infection and Myocarditis: A State-of-the-Art Systematic Review

“… 11 As of September 1 2021, the Centers for Disease Control and Prevention writes that the risk of myocarditis is far higher after COVID-19 infection as opposed to the mRNA virus. 12 Based on a study that identified 1.5 million inpatient records with COVID-19, myocarditis was uncommon among patients with or without COVID-19, however, there was a relatively higher risk in the 50 to 75 and over age groups. 12 The under 16 age group could be more prone due to the related multisystem inflammatory syndromes.…”

“… 12 Based on a study that identified 1.5 million inpatient records with COVID-19, myocarditis was uncommon among patients with or without COVID-19, however, there was a relatively higher risk in the 50 to 75 and over age groups. 12 The under 16 age group could be more prone due to the related multisystem inflammatory syndromes. 12 The paper also noted an 18-fold higher chance of developing myocarditis due to COVID-19.…”