the risk of portal vein thrombosis appears to be 30 times higher with mRNA vaccines (Pfizer and Moderna) than with AstraZeneca’s. The risk of cerebral vein thrombosis, which caused many regulators to pause or discontinue using AstraZeneca’s and J&J vaccines, appears to be very similar for AstraZeneca’s vaccine (5 in a million) as for Pfizer’s and Moderna’s mRNA vaccines (4 in a million).