This could be due to heparin resistance and lower levels of anti-activated factor X in these patients, which could be attributed to high levels of fibrinogen and reduced antithrombin levels in COVID-19 patients, yet the exact mechanism for heparin resistance among COVID-19 patients is not known.54 Therefore, it is recommended to use higher doses of prophylactic anticoagulant, as it was reported that with higher doses the levels of anti-activated factor X are higher, which could aid in preventing thrombosis. This evidence concerns the gene F10 and COVID-19.