If i were in your place, I’d stick to my current fasting protocol as far as I’ve been doing it for a while. However I’d steer clear of extended fasts for a few weeks. Lastly, if I start showing symptoms, consult a process on what to do
This is something you should be asking a doctor, honestly.
Having had Covid before the vaccines existed, my personal recommendation is to eat. Give your body the nutrition and energy (i.e. calories) it needs to support your immune system. I’ve personally never heard that adage before, and it sounds like it’s based on bad science or an old wives’ tale.
You can restart fasting when you’re well, but lacking the proper nutrition could extend your time being sick. A few days of good rest and eating well won’t throw off your weight loss journey that much, after all.