Hey there,
I'm a current 4rth year DO student going into DR and have been grappling with VSAS. Are you trying to get away rotations this year? Or for your 4rth year?
If it's for your 4rth year, you should probably start at least kinda looking around in February for what programs you want to rotate at and what their requirements are.
If you are looking for stuff this year, it has been VERY difficult to snag rads rotations in the fall for us 4rth years because of the increased requirements for rotating at different institutions (e.g. on program in particular I wanted to rotate at required you be in a bordering state with no home radiology program and attend an LCME-accredited school (so... an MD school... despite being a very DO-friendly program.)) I've had success with one rotation on VSAS for radiology in my home state where I have close personal ties. Aside from this, I have only been able to secure a rotation because I knew someone in the scheduling department at a university here in the KC, MO.
I do think as the year progresses, it will become much easier to snag away rotations (e.g. January & beyond) because less 4rth years are going to be applying for those if you are looking for stuff in that time range. If you are looking for something like this, applications are open now at a lot of places and you should probably be applying for them so you can secure them.
As to what the guidelines are with COVID & radiology rotations, it is completely program-dependent so you'll have to go onto the programs' websites you are interested in, go to their "visiting students" section, & read what they have about COVID on there. If you have any questions, they usually have a coordinators' contact information you can use to reach out.