Can Li, Yanxia Chen, Yan Zhao, David Christopher Lung, Zhanhong Ye, Wenchen Song, Fei-Fei Liu, Jian-Piao Cai, Wan-Man Wong, Cyril Chik-Yan Yip, Jasper Fuk-Woo Chan, Kelvin Kai-Wang To, Siddharth Sridhar, Ivan Fan-Ngai Hung, Hin Chu, Kin-Hang Kok, Dong-Yan Jin, Anna Jinxia Zhang, Kwok-Yung Yuen, Intravenous Injection of Coronavirus Disease 2019 (COVID-19) mRNA Vaccine Can Induce Acute Myopericarditis in Mouse Model, Clinical Infectious Diseases, 2021;, ciab707, https://doi.org/10.1093/cid/ciab707
Post-vaccination myopericarditis is reported after immunization with coronavirus disease 2019 (COVID-19) messenger RNA (mRNA) vaccines. The effect of accidental intravenous injection of this vaccine on the heart is unknown.
We compared the clinical manifestations, histopathological changes, tissue mRNA expression, and serum levels of cytokine/chemokine in Balb/c mice at different time points after intravenous (IV) or intramuscular (IM) vaccine injection with normal saline (NS) control.
Although significant weight loss and higher serum cytokine/chemokine levels were found in IM group at 1–2 days post-injection (dpi), only IV group developed histopathological changes of myopericarditis as evidenced by cardiomyocyte degeneration, apoptosis, and necrosis with adjacent inflammatory cell infiltration and calcific deposits on visceral pericardium, although evidence of coronary artery or other cardiac pathologies was absent. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike antigen expression by immunostaining was occasionally found in infiltrating immune cells of the heart or injection site, in cardiomyocytes and intracardiac vascular endothelial cells, but not skeletal myocytes. The histological changes of myopericarditis after the first IV-priming dose persisted for 2 weeks and were markedly aggravated by a second IM- or IV-booster dose. Cardiac tissue mRNA expression of interleukin (IL)-1β, interferon (IFN)-β, IL-6, and tumor necrosis factor (TNF)-α increased significantly from 1 dpi to 2 dpi in the IV group but not the IM group, compatible with presence of myopericarditis in the IV group. Ballooning degeneration of hepatocytes was consistently found in the IV group. All other organs appeared normal.