Participants: Persons of all ages and sex included in studies that reported cardiac complications in either COVID-19 vaccines or due to COVID-19 infection group.
Intervention/Exposure: 1) COVID-19 vaccines and 2) SARS-CoV-2 infection.
Comparison: 1) Non-vaccinated group and 2) Individuals without infection.
Outcome of interest: Myocarditis.
Study type: Randomized clinical trials (RCT) and observational studies.