We are now entering a critical period during which we will move rapidly through phased vaccination of various priority subgroups of the population. In response to the cases of anaphylaxis associated with the Pfizer–BioNTech vaccine in the United Kingdom and now several cases of anaphylaxis in the United States, the CDC has recommended that only persons with a known allergy to any component of the vaccine be excluded from vaccination. A systematic approach to the existing hypersensitivity cases and any new ones will ensure that our strategy will maintain safety not only for this vaccine but for future mRNA and SARS-CoV-2 vaccines with shared or similar components (Figure 1 and Table 1).6