Risk stratification through allergy history: single-centre experience of specialized COVID-19 vaccine clinic

Anaphylaxis is a rare side-effect of COVID-19 vaccines. To (a) provide direct advice and reassurance to certain persons with a history of anaphylaxis/complex allergy, in addition to that available in national guidelines, and (b) to provide a medically supervised vaccination, a specialist regional vaccine allergy clinic was established. The main objective was to determine if risk stratification through history can lead to safe COVID-19 vaccination for maximum population coverage. A focused history was taken to establish contraindications to giving COVID-19 vaccines. People who reported a high-risk allergy history were given a vaccine not containing the excipient thought to have directly caused previous anaphylaxis. All vaccines were monitored for 30 min after administration. A total of 206 people were vaccinated between 6 July 2021 and 31 August 2021; Comirnaty (Pfizer-BioNTech) (n = 34), and Janssen (n = 172). In total, 78% were women. Ninety-two people (45%) reported a high-risk allergy history. There were no cases of anaphylaxis. Three people developed urticaria and one of these also developed transient tachycardia. One vaccinee developed a pseudoseizure. Two of 208 people (<1%) referred during this time declined vaccination based on personal preference, despite the assessment of low clinical risk. In our experience, all vaccines with high-risk allergy histories were administered Pfizer BioNTech or Janssen Covid-19 vaccines uneventfully following screening based on allergy-focussed history. Our data support that drug allergy is not associated with a higher risk of vaccine-related anaphylaxis but may act to guide the administration of alternate vaccines to people with polyethylene glycol/polysorbate 80/trometamol allergies or anaphylaxis after the first dose. Individuals with complex allergy histories have experienced COVID-19 vaccine delay and there have been many reports of both immediate and delayed reactions to prior COVID-19 vaccination doses. The study demonstrates a successful strategy for vaccinating the majority of people with documented allergy history, showing those deemed high-risk can be vaccinated safely following screening based on an allergy-focussed history, without need for allergy investigation (e.g. skin prick testing) prior to vaccination. The results of this study act as reassurance of vaccine safety and can be used to guide future community vaccination management of persons reporting drug/food allergy history.