Not sure what you mean. They had several arms of the experiment. I think a control, a low dose, and a maybe one or two higher dose. After a few months the results seemed to indicate that some people in the experiment were producing antibodies. The fda told them they could expand the study to do an additional round of vaccines - like a booster. When the study was unblinded I found out I was in the highest dose arm of the study and had also received the booster.

Running experiments is hard and costly- especially ones that unfold over a long time son they can’t go on indefinitely.