Once You Make Initial Cuts..
The time has come to establish some sort of rule for cutting, such as family only. To avoid hard feelings, the last thing you want is to make your decision seem arbitrary. You might even consider a virtual option whereby disinvited guests are asked to participate via digital access.
When you decide on numbers and who you are cutting from the list, it is important to make personal connections with those you are uninviting. A phone call is the best way to chat personally and explain your situation. If not, then the best etiquette is to send a personalized card.
The message you convey will also go a long way toward saving hurt feelings. Begin by emphasizing how difficult your decision is and that it is made absolutely out of concern for the health of all involved. A nice way to make the ex-guest feel important is to tell them there will be a full celebration at a later (post-COVID) date where you will be eager to see them. Or, if a party is already part of your smaller plans, you might suggest that you would like to get together with them later one-on-one.