What about serious allergic reactions?
Here is what the checked sources say. Each title links to the original.
Risk of anaphylaxis after vaccination in children and adults
Using medical records from the US Vaccine Safety Datalink for 2009 to 2011, researchers found 33 confirmed cases of vaccine-triggered anaphylaxis, a severe and potentially life-threatening allergic reaction, after 25,173,965 vaccine doses: about 1.3 cases per million doses. The rate did not differ much by age. Most reactions began within 4 hours. The authors conclude anaphylaxis after vaccination is rare. One co-author disclosed research support from several vaccine makers.
Reports of Anaphylaxis After Receipt of mRNA COVID-19 Vaccines in the US-December 14, 2020-January 18, 2021
In the first weeks of mRNA COVID-19 vaccination (December 14, 2020 to January 18, 2021), 66 reports to VAERS met the case definition for anaphylaxis among about 17.5 million doses: 4.7 per million Pfizer doses and 2.5 per million Moderna doses. Median onset was about 10 minutes, and about a third of people had a past history of anaphylaxis to something else. Nearly all received epinephrine; no deaths were reported. At the time, the authors noted a 15-minute wait was recommended for everyone, and 30 minutes for people with certain allergy histories.
Vaccines and Allergies: What You Should Know
A 2018 parent handout. Allergic reactions to vaccines do happen, rarely, and are usually to an ingredient. CHOP advised that anyone who had a severe reaction to a vaccine should not get more doses of it, and that people with milder ingredient allergies talk to their provider. Gelatin causes the most allergic-type reactions, about one severe reaction per 1.2 million doses. As of 2018, CHOP said egg- allergic people can get flu vaccine, yellow fever vaccine still needs an allergist, and peanut and corn allergies are not reasons to skip any vaccine.