The Trend of Myocarditis in Mississippi Before and During the Covid-19 Pandemic Era

There has been an increased awareness of the inflammation of the heart called myocarditis recently. This inflammation, which causes abnormal heart rhythms can be triggered by the immune system's response to viral infections such as the COVID-19 virus. Recent reports suggest a causal link between COVID-19 and myocarditis. This study aims to compare the trend of myocarditis in Mississippi before the COVID-19 era (2016 – 2019) and during the COVID-19 pandemic (2020-2021). A retrospective study of hospitalizations for myocarditis in the state of Mississippi from 2016 to 2019 was conducted. Then, a record of hospitalization of patients with co-morbidity of myocarditis and COVID-19 from April 1, 2020, to March 31, 2021, was obtained for comparison. All data are from the Mississippi State Department of Health. The hospitalization rate for myocarditis was stable at an annual average of 65 persons between 2016 and 2019. In 2020, 118 hospitalizations representing an 82% increase in hospitalization were recorded. Also, the hospitalization rates were 17 per 100,000 in the pre-COVID era but increased by 100% to 34 per 100,000 hospitalizations during the pandemic. The proportion of COVID-19 patients with myocarditis was highest at the beginning of the pandemic (62% in the second quarter of 2020). By the first quarter of 2021, the proportion has decreased to 48%. There was a spike in the number of myocarditis cases between 2020 and 2021. However, the proportion of myocarditis patients with COVID-19 hospitalization declined steadily from the second quarter of 2020. Since the COVID-19 vaccination started in January 2021, the rise in the cases of acute myocarditis in 2020 may not be attributable to the COVID-19 vaccination. An understanding of the trend of myocarditis and its association with COVID-19 will strengthen the health promotion campaign on vaccination and other COVID-19 prevention strategies