Which component found in some RNA-based vaccines may trigger allergic reactions in certain individuals?

Which component found in some RNA-based vaccines may trigger allergic reactions in certain individuals?

• A. PEG solution
• B. Aluminum salts
• C. Mercury
• D. Gelatin

Answer: (A)

Allergic reactions to vaccines can be triggered by excipients—substances added for stability or delivery rather than the active ingredient. In RNA-based vaccines, the stabilizing component is polyethylene glycol (PEG) in the lipid nanoparticle that carries the mRNA. Some individuals have preexisting anti-PEG antibodies, and a small number may experience immediate hypersensitivity reactions, including anaphylaxis, after vaccination. This makes PEG the component most associated with allergic reactions in these vaccines. Aluminum salts are adjuvants used in many traditional vaccines to boost the immune response, but they are not part of the RNA-based vaccines. Mercury-containing compounds are not used in these vaccines either. Gelatin can be a stabilizer in some vaccines, but it is not a characteristic feature of RNA-based vaccines, so it is less likely to be involved here.

Allergic reactions to vaccines can be triggered by excipients—substances added for stability or delivery rather than the active ingredient. In RNA-based vaccines, the stabilizing component is polyethylene glycol (PEG) in the lipid nanoparticle that carries the mRNA. Some individuals have preexisting anti-PEG antibodies, and a small number may experience immediate hypersensitivity reactions, including anaphylaxis, after vaccination. This makes PEG the component most associated with allergic reactions in these vaccines.

Aluminum salts are adjuvants used in many traditional vaccines to boost the immune response, but they are not part of the RNA-based vaccines. Mercury-containing compounds are not used in these vaccines either. Gelatin can be a stabilizer in some vaccines, but it is not a characteristic feature of RNA-based vaccines, so it is less likely to be involved here.