Less than a year after the first detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), vaccines have been approved for routine use in numerous countries and have already been used in mass vaccination programs. Vaccines include the mRNA BNT162b2 and mRNA 1273. Allergic reactions and anaphylaxis account for a substantial proportion of the adverse reactions to these vaccines observed to date, but overall they are rare. The incidence of anaphylaxis in the context of SARS-CoV‑2 vaccination with the mRNA vaccines appears to be approximately 10-fold higher than with previous vaccines, at approximately 1 per 100,000 vaccine injections. One focus of the present article is a systematic review of the components of mRNA vaccines against “ coronavirus disease 2019 ” (COVID-19). Differences from established vaccines are addressed and the allergic potential of liposomes, polyethylene glycol, tromethamine/trometamol, and mRNA are discussed. Another focus is on the clinical presentation and course of allergic reactions to the COVID-19 vaccines. This is followed by a discussion of the therapeutic approach to anaphylactic reactions, as well as the drugs and medical supplies required to treat them. It is important to note that any vaccinee may be affected by anaphylaxis, regardless of whether or not allergic diseases are already known. Therefore, every vaccination site and every vaccinator must be prepared to recognize and treat severe allergic reactions.