Many have asked about Penicillin, shellfish, other allergies & risk of #Covid19 vaccine reactions. Does it increase your risk? The short answer is NO. But let's dig deeper to answer some related questions while we're at it 1/

"Killed vaccines" for #Covid19 don't contain live virus. The active ingredient is eg. synthetic RNA (Pfizer/Moderna) or weak protein from another virus used as a "vector"- Astra Zeneca, Janssen). Possible to develop severe rxn to this but very RARE 2/

From my excellent colleage @DavidJuurlink, very reassuring data from CDC so far about safety and very low risk of severe reactions with > 1 M doses administered to date. 3/

Most allergic reactions appear to be driven by the non-active ingredients in a vaccine formula. Minor differences between vaccines but in general, these are:
salts, sugars, water, lipids, alcohols, other stabilizer compounds 4/

Because Penicillin, shellfish, peanuts, environmental allergens share little to no structural similarity to the vaccine ingredients, there is very little likelihood of our immune system "screwing up" and mistaking one for the other to trigger allergic rxn 5/

Still possible to have a severe rxn these allergies? Of course, but feel reassured, that:
1. There is no predictive correlation between a history of allergies & vaccine rxn
2. Severe rxns are rare & post-vaccination monitoring is standard in most places 6/

At end of day, most likely result of vaccine = fleeting symptoms (sore arm, mild temp, aches, pains x 24-48 h) to prevent something much more dangerous that could cause serious harm or loss of life. For me, easy choice. 7/ #BeGreatVaccinate

Contrary to what you may have read on the wrong health education forum, "Ana Phylaxis" is not a Greek belly dancer. Get your info from credible sources. Knowledge is safety. Safety is everyone's business. 8/ End