I just fasted for 12 days and feel it’s important to keep my insulin low and level. I feel great too. My morbidly obese neighbor died, when you have high insulin it decreases your D and immune system. I’d keep doing what you’re doing.
The efficacy of Covid vaccines haven’t been tested in a fasted state. Given that the resource (vaccine) is limited, I would recommend that you err on the side of caution and avoid fasting 2-3 days (maybe longer after) before and after you get the vaccine.
I stopped fasting a few days before the vaccine and two weeks after. Both doses provoked a strong immune response. I have no science to back up my behavior, but I somehow felt better knowing my body was in food burning mode while fighting the vaccine.
I’ve returned to my normal fasting shenanigans now.