Hello @Anna170
May I suggest rather than cancel bookings between yourselves and your intended guest that you reach out and offer the option to make an "Alteration" to the dates they have booked and tentatively make a booking that may suit both parties for in the future.
That way it's win-win and all parties have something to look forward to in future.
Your Guests are probably equally as disappointed as yourselves and will be looking forward to a Get-away without the disruptions.
Look at it this way, they chose your home for a reason, and it would be great if they and you could still in future go forward with your bookings.
It would also offer your Guests some Peace of Mind for the future to offer and undertake a "Date Alteration" so they don't need to start searching for accommodation elsewhere.
Encourage open communication and keep in touch with each other via the Message system.
If you use related keywords here in ABB CC search-box you will find others who have had similar experiences to what you and your Guests are currently experiencing.
All the very best for a return to normality in this crazy world.