Participants will continue to be monitored for the next 2 years. This just marks the point at which Pfizer can claim their vaccine to be more than 30% effective.

They will unfortunately vaccinate the placebo arm as soon as they get the EUA. At this point the study would be mostly unblinded, so far as I can tell, there will also be a much smaller, if any control group.

“If our potential vaccine receives an EUA, we would propose amending the study protocol to create a process so that interested, eligible participants who received the placebo could ‘cross-over’ to the vaccine arm of the study,”