Sara Anvari, MD, MSc: Urticaria and Angioedema Events Following COVID-19 Vaccination

Most cases had onset after 4 hours and were mild, which Dr. Anvari noted should not contraindicate future COVID-19 vaccine doses.

A new investigation into urticaria and angioedema following mRNA COVID-19 vaccination found that U/AE events comprised 13% of clinician reported COVID-19 vaccine allergy cases in the COVID-19 Vaccine Allergy Case Registry of Massachusetts General Hospital.

Events occurred between February 13, 2021 and October 22, 2021, with a majority occurring without underlying chronic U/AE. However, most cases had onset after 4 hours and were mild, which investigators noted should not contraindicate future COVID-19 vaccine doses.

The study will be presented at the American Academy of Allergy, Asthma & Immunology Annual Meeting (AAAAI) 2022.

In an interview with HCPLive, Sara Anvari, MD, MSc, Assistant Professor of Pediatrics at Baylor College of Medicine and Texas Children's Hospital, spoke of the registry that was developed by Dr. Kimberly Blumenthal and the immediacy of U/AE reactions following vaccination.

“What was really surprising was to see the amount of reports in this registry with regards to urticaria and angioedema, and we saw that the majority of the cases occurred at 24 hours or beyond,” Anvari said. “We saw close to 50% of the cases that were in the registry during the initial evaluation that happened during that timeframe, and then we saw up to about 35%, occurring within the first 4 hours. What was interesting was the resolution took relatively more than 24 hours for more than about 50% of these individuals who reported these cases.”

Of the 455 cases studied, the amount of events for both the Pfizer and Moderna vaccine were equal and no reported cases were observed for the Johnson & Johnson vaccine.

Anvari and colleagues noted that 40% of patients in the cohort had an allergic disorder, which included nasal allergies, asthma, and eczema. The team believed these factors potentially predisposed patients to U/AE events following vaccination.

Interestingly, this and other studies have shown that female patients make up a majority of reported reactions.

“What we do see that these are resolving issues, some of them self-resolving, and to the extent that having a urticaria angioedema event can be treated appropriately with long acting antihistamines,” Anvari said. “So keeping that in mind, this could help alleviate the symptom, and one shouldn't worry about the potential of having this go on into anaphylaxis.”

A majority of U/AE events occurred at home, with approximately 25% of individuals visiting the emergency room more out of concern rather than necessity.

“For those who did require treatment, we can see that a majority of the individuals, up to 70% of them, had been treated with some form of anti-histamine followed by oral steroids,” Anvari said. “So these are kind of an indication to us that the severity is not that significant. Most individuals would find themselves having resolution of this in a relatively short time, and this would not be a contraindication to receiving the second (COVID-19 vaccine) dose.”