COVID-19 Vaccine-Related eConsults: Case 2

eConsult Clinical Question:

Patient with urticarial rash developing one week after Moderna COVID vaccination dose with no clear alternate inciting exposure. Could the COVID vaccine be responsible for the rash given the rash began one week after the vaccine? Can she receive the second dose of COVID vaccine? 

eConsult Response:

The patient can receive the second dose, but I recommend monitoring her for 30 minutes post-vaccine rather than 15 minutes. There have been reports of a delayed localized rash about 7-10 days following the Moderna COVID vaccine. It is unclear why it occurs with the Moderna but not the Pfizer vaccine. The first dose reaction did not always translate to a similar rash with the second dose.  

What is unusual here is that this patient's rash is more global without much mention of an injection site problem which is what has been reported with the Moderna vaccine. We can see delayed rashes with vaccines but do not deem this a predictor for future allergic reactions. The concern for immediate type hypersensitivity as currently defined by the CDC for the COVID vaccine is within 4 hours of vaccination. With current CDC guidelines, there is no contraindications for the second COVID vaccine. The patient can follow up in Drug Allergy clinic for further evaluation if there is concern for an allergy any components of the vaccine. 

These real-life examples have some limitations. Given the evolving recommendations and guidance on COVID-19 care, these cases should not be considered complete or definitive and may not reflect the most up-to-date guidance.