Well, I'm in a covid vaccine study as of a few days ago. Got my fourth dose, and it's a new version of the vaccine that is more specifically geared towards fighting the Omicron variant. The only thing I don't know (the "blind" part, for now) is how big of a dose I got. I suspect it was less than the usual dose, because I haven't been sick after taking it. A little tired, slightly "off," but nothing like previous doses where I stayed in bed until noon.
Despite discussing it at length before going, to different people on different calls, they rejected my spouse for being type I diabetic. That's annoying.
My hope is if/when the variant of the Omicron variant gets over here from Europe, I'll have a bit of an edge against it, and also help them get enough testing done to roll it out to others.