Key findings: * In this study of over 500,000 COVID-19 patients, CVT occurred in 39 in a million patients. * In over 480,000 people receiving a COVID-19 mRNA

Key findings: * In this study of over 500,000 COVID-19 patients, CVT occurred in 39 in a million patients. * In over 480,000 people receiving a COVID-19 mRNA vaccine (Pfizer or Moderna), CVT occurred in 4 in a million. * CVT has been reported to occur in about 5 in a million people after first dose of the AZ-Oxford COVID-19 vaccine. * Compared to the mRNA vaccines, the risk of a CVT from COVID-19 is about 10 times greater. * Compared to the AZ-Oxford vaccine, the risk of a CVT from COVID-19 is about 8 times greater.