Since late of 2019 COVID.19 represent the most widespread pandemic affect the globe , due to its quick spread, rapid evolution of the virus and imbalance between medical research and viral development and progression. Despite presence of several therapeutic protocols and fast synthesis of vaccine to the virus, it still the top problem facing the world. Presence of vaccine to COVID.19 in short time is the outcome of an excellent work of medical researchers, but dilemma observed as presence of abnormal coagulation disorders after usage of certain types of COVID.19 vaccines.Heparin is forbidden for thrombosis resulted from COVID.19 vaccine, simply this is due to inactivated coagulation factor (factor XI) content in these vaccines, which may lead to deactivation of heparin in presence of thrombin and fibrin clot, we recommend to use pentasaccharide danaparoid anticoagulants to resolve vaccine resulted thrombus.