- who have received convalescent plasma for covid-19, - who have known hypersensitivity to plasma, - who are pregnant, - who the clinical team has decided not to escalate therapy (except that for cardiac arrest; patients who are not for cardio-pulmonary-resuscitation may be enrolled). - who have received rrt for more than 72 hours - who have received mechanical ventilation for more than 14 days - we will not exclude patients enrolled in other interventional trials unless the protocols of the two trials collide (e.g. use of ccp by protocol). co-enrolment agreements will be established with the sponsor/investigator to maintain an updated list of trials approved for co-enrolment (

- who have received convalescent plasma for covid-19, - who have known hypersensitivity to plasma, - who are pregnant, - who the clinical team has decided not to escalate therapy (except that for cardiac arrest; patients who are not for cardio-pulmonary-resuscitation may be enrolled). - who have received rrt for more than 72 hours - who have received mechanical ventilation for more than 14 days - we will not exclude patients enrolled in other interventional trials unless the protocols of the two trials collide (e.g. use of ccp by protocol). co-enrolment agreements will be established with the sponsor/investigator to maintain an updated list of trials approved for co-enrolment (