Delayed reaction to mRNA COVID-19 vaccine
Question:
2/18/2021
A 70 year-old woman with delayed reaction to first COVID-19 Moderna vaccine. No significant atopic history. She developed on day 8 local swelling, rash, and itching at injection site (Not concerned). On day nine developed myalgias, arthralgias (no arthritis), unilateral upper and lower eyelid edema. No rash or skin itching. No fever but felt like she had the flu. Seen at urgent care COVID-19 test negative diagnosed as serum sickness to vaccine. Delayed symptoms waxed and waned for eight days now feeling better. Personally, I'm not convinced true serum sickness would like thoughts on this? No lab studies for done I have ordered but she at tail end of symptoms. Would you recommend second vaccine in this patient? If true serum sickness would you vaccinate with second dose?
Answer:
Unfortunately, I do not think there is any means by which you can determine the mechanism responsible for the symptoms and signs described. A delayed reaction, perhaps related to humoral immunity with or without complement activation, could explain the symptoms. If so, the second dose with the amanestic immune response could make the severity of the ‘reaction’ greater following the second dose. I do not think measurement of IgG antibody to SARS-CoV-2 would be of help. The reaction you described is not a contraindication for the second dose as it does not qualify as a severe allergic reaction or immediate allergic reaction to the first dose (1).
I suggest a shared decision-making discussion of the risks of not giving the second dose of the mRNA vaccine, such as potential of waning immunity and reduced protection from a life-threatening infection, versus the potential of a more severe, though probably not life threatening, reaction to the second dose. Another option might be a delay in the second dose, but there are no guidelines or laboratory assessments to inform you as to the optimal time for the second dose. Information from Israel and the UK suggest that a single dose of the mRNA vaccine is more than 85% effective but duration of protection is unknown (2). Administering a different type of vaccine for the second dose has not been studied.
In summary, I favor administering the second dose along with oral NSAID for 10-14 days following the vaccine, assuming there are no contraindications. I would prefer to avoid oral corticosteroid therapy for fear this may impair or reduce the immune response. Measurement of CH50, C4, C3, CBC, U/A, CBC and ESR before the second dose and repeat if symptoms develop may be of value in assessing the mechanism and informing additional treatment options.
1. Interim Clinical Considerations for Use of mRNA COVID-19 Vaccines | CDC
2. Pfizer COVID Vaccine Highly Effective After One Dose: Study (nymag.com)
I hope this information is of help to you and your practice.
All my best.
Dennis K. Ledford, MD, FAAAAI