How can it be a randomized controlled trial? Did they randomize a group from the general population in advance and then randomly and blindly, but in a controlle

How can it be a randomized controlled trial? Did they randomize a group from the general population in advance and then randomly and blindly, but in a controlled fashion, infect part of the subjects and did they then consider the effects without looking at whether they were the infected people or the control group, until the conclusion of the study? That’s what’s require for the gold standard.