NO. They are not permanently dismissed or discharged. The leadership is trying to reduce the social contact, or what I would call the "sardine affect" of 4000+ cadets in confined areas. They are working to continue online or remote classes for all preppies and cadets for the remainder of the year, including those remaining on campus. As far as 2021 prep school and 2024 Academy appointees, as the website states, everything is very dynamic at this time. The US and military leadership is trying to keep things as much on track as possible. No one, including the leadership knows at this point in time how the incoming classes will be affected, if at all.
Relax! Keep yourself safe and well. Stay updated by monitoring the official USAFA website. Control what you can.