Covid vaccines don't contain MRC-5 (some other vaccines do). You could just say your vegan or vegetarian - Pfizer vaccine contains mNeonGreen protein/DNA marker used with genome editing. It's derived from fish protein (Aequorea Victoria or Branchiostoma lanceolatum) - https://thedonald.win/p/11QlPDv12E/very-weird----pfizer-vaccine-con/

Covid vaccines dont contain MRC-5 (some other vaccines do).