Related covid vaccine production many different strategies was followed by the producers.Observing some rare event of thrombosis after vaccination, by some vaccine, it is interesting to verify if the Target used for the manufacturing can be involved in an different procoagulant activity or not.Some vaccine are suspended or under a deep new verify- investigation by the regulatory agency.This fact it is relevant.The target SPIKE-PROTEIN FULL LENGTH modified or not or towards the RBD domain can be a relevant factor.