Uninviting

I would just call or text people and say for the safety of everyone you are changing it to family/wedding party only! I feel like everyone would completely understand at this time. We all need to look out for each other and you’re definitely doing the right thing as much as it sucks. I’m so sorry you’re dealing with this.

I agree with the above. If you are planning on rescheduling for a reception I would also mention that that will be considered later and that a letter will be received. I am sure all of your guests will appreciate your change in plans with their health in mind! Congratulations on your marriage!

While this would normally be rude, these are not normal times! I agree with the people above and you could limit to family/wedding party only. Given these crazy circumstances which are beyond your control, I absolutely think people would understand.

Do keep in mind though, that many states are currently limiting gatherings to 25 people or less. In a week from now, the 50 rule could be 25 or even less in your state...So sorry you have to deal with this, and don't worry--people will understand!

I think the PPs have covered it... not rude given the circumstances. People will understand and honestly may be relieved. They may be trying to figure out how to tell you they aren’t coming without hurting your feelings.
I say if you send a letter, send it to even those that declined. If you are calling/texting then just to those that were a yes.
Then if you plan a reception for a later date go back and re-invite those that have declined.