'Stunning' 620% Higher Risk of Myocarditis After mRNA COVID Vaccines --A peer-reviewed study of 9.2 million South Koreans published in Nature Communications uncovered a 620% increased risk of myocarditis and 175% higher risk of pericarditis following mRNA COVID-19 vaccination. Researchers also noted increased risks of several autoimmune conditions, especially after booster doses. | 26 July 2024 | A large-scale peer-reviewed South Korean study has found significantly increased risks of serious cardiac and neurological conditions following mRNA COVID-19 vaccination, and lesser risks of several autoimmune diseases. The nationwide population-based cohort study, published Tuesday in Nature Communications, followed nearly 4.5 million people for an average of 15 months after vaccination. Researchers found a striking 620% increased risk of myocarditis and 175% increased risk of pericarditis in people who received the vaccine compared to historical controls. The study also revealed a 62% increased risk for Guillain-Barré syndrome (GBS), a rare neurological disorder.