I guess you ensure exposure by having many test subjects during an ongoing pandemic...
Now that the UK have already over 500k doses of the other vaccine administered we will see new data on the effectiveness and safety of the vaccine (in comparison to CoVid-19, don't forget that!).
Now that the UK have already over 500k doses of the other vaccine administered we will see new data on the effectiveness and safety of the vaccine (in comparison to CoVid-19, don't forget that!).