Maryland is the other one I know of for sure. According to the B10 coaches, this is where their percentages are currently:
Northwestern 90-95%
Indiana, Maryland, Minnesota, Rutgers, and Michigan all >90%
Wisconsin 85%
Penn State "well over 70%" and pushing hard to get to 100%
Ohio State is pushing for 100%, but they have a ways to go (still ahead of Iowa)
Illinois is pushing hard to get everyone vaxxed prior to fall practice starting.
A June case at Iowa already affected off season workouts for a number of players. Our margins are so thin any way, this could be the factor that will swing a game or two into the loss column that would have otherwise gone our way. I'm not very optimistic that this won't negatively affect us down the road. If Ferentz isn't pushing hard and educating the players on this, then he's really not doing his job well, not at all.