Originally Posted by Peter Snijder

[Edit: I realize this is a bit OT since the OP stated he/she can't reschedule and would instead ask for flight credit]

I contracted Covid during a transatlantic trip recently and had to reschedule my return trip. While the airline (AA) allowed me to reschedule without a change fee, the fare difference was close to $500. I had signed up for travel insurance that specifically covered costs incurred because of covid infection (flight changes, medical treatment, etc.), and that turned out to be some well-spent money (around $40). That doesn't mean that I encourage everyone to sign up for travel insurance, but as long as the US requires a negative test before traveling to the US, it may be a good investment.