Wikipedia tells me RCT is "randomized controlled trial", that thing they are doing where half the volunteers receive the experimental vaccine and half receive a

Wikipedia tells me RCT is "randomized controlled trial", that thing they are doing where half the volunteers receive the experimental vaccine and half receive a placebo, and they wait to see how many get the disease (and how many get side effects) in each group. I don't think there's any "human challenge study" (in which they deliberately infect the volunteer, https://en.wikipedia.org/wiki/Human_challenge_study https://en.wikipedia.org/wiki/Human_challenge_study) so far.