evidence: - Pfizer-BioNTech and Moderna COVID-19 vaccines which are mRNA vaccines. [...] Pfizer-BioNTech and Moderna mRNA COVID-19 vaccines mRNA vaccines use mRNA created in a laboratory to teach our cells how to make a protein—or even just a piece of a protein—that triggers an immune response inside our bodies. The mRNA from the vaccines is broken down within a few days after vaccination and discarded from the body. [...] - If you are allergic to polyethylene glycol (PEG), you should not get Pfizer-BioNTech or Moderna COVID-19 vaccines.