The CoVid-19 vaccines have been produced in record time. As such, we have a very limited database of possible side effects and virtually no knowledge of possible long term effects simply because it is too new. There have been reports of people having severe anaphylaxis reactions to the injections. I get that from yellowjacket wasp stings, not fun. Scientists think that it may be from the polyethylene glycol.
Britain's medicine regulator said anyone with a history of anaphylaxis to a medicine or food should not get the Pfizer-BioNTech COVID-19 vaccine, giving fuller guidance on an earlier allergy warning about the shot.