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A patient of mine who received first dose of Moderna vaccine experienced difficulty breathing and throat swelling an hour after the vaccine was administered. She was administered epinephrine at the center. Should she receive the second dose? Can J&J be administered instead of the second dose of Moderna to be on the safe side?


When assessing reactions to vaccine, the Brighton Collaboration criteria is used (1,2). The Brighton scale identifies major and minor criteria and assigns a clear definition for anaphylaxis. The history provided supports a single organ system involvement, with throat tightness and respiratory distress within an hour after receiving the Moderna Vaccine. While concerning, this alone does not meet that criteria. This may represent anxiety and/or paradoxical vocal fold movement (vcd).

This brings up several questions. Were there other symptoms / other organ systems involved? Was a tryptase drawn? What is her basal tryptase? Does she have a prior history of anaphylaxis or other co-morbidities? What was her response to the epinephrine?

Based on the symptoms reported, without additional information, I would NOT think she was a candidate for the second dose of the mRNA COVID-19 vaccine. This is based on a change in the CDC guidelines on December 30, 2020 (3) “Immediate allergic reaction of any severity to a previous dose of an mRNA COVID-19 vaccine” should not receive second vaccine.

If she has not experienced immediate reactions to other vaccines (containing polysorbate), she would be a candidate for the Janssen Vaccine and observed at least 30 minutes afterward. I recommend shared decision making with a thorough discussion of risk-benefit ratio. If not already done, I recommend you obtain a basal tryptase level and draw a level within two to three hours of a subsequent reaction.

1) McNeil MM, Weintraub ES, Duffy J, Sukumaran L, et al. Risk of anaphylaxis after vaccination in children and adults. J Allergy Clin Immunol. 2016 Mar;137(3):868-78. doi: 10.1016/j.jaci.2015.07.048. Epub 2015 Oct 6. PMID: 26452420; PMCID: PMC4783279.

2) Rüggeberg JU, Gold MS, Bayas JM, et al. Brighton Collaboration Anaphylaxis Working Group. Anaphylaxis: case definition and guidelines for data collection, analysis, and presentation of immunization safety data. Vaccine. 2007 Aug 1;25(31):5675-84. doi: 10.1016/j.vaccine.2007.02.064. Epub 2007 Mar 12. PMID: 17448577.

3) Interim Clinical Considerations for Use of mRNA COVID-19 Vaccines Currently Authorized in the United States

I hope to find this helpful.

Respectfully submitted,
Jeffrey G Demain, MD, FAAAAI

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