INTRODUCTION
Mass vaccination was the main strategy to contain the COVID-19 pandemic. Very early in the vaccination campaign, hypersensitivity reactions were reported, (Ahmadi et al, Chu et al). Adverse reactions occurring between a few minutes, hours or few days after COVID-19 vaccination are quite common with some of these reactions resembling symptoms that are seen in allergic reactions, like urticarial rash, angioedema, shortness of breath, wheezing, nausea, and hypotension (Jaggers et al, Abbaspour et al). Also, during the pandemic, some persons were not vaccinated out of precaution due to a possible or confirmed allergy to one of the excipients of the COVID-19 vaccine like polysorbate 80 or polyethylene glycol (PEG) Krantz et al).
In the Netherlands, the National Institute for Public Health and the Environment (RIVM) published vaccination guidelines that are followed up by the Municipal Health Service (GGD) that was in charge of the Covid-19 vaccination campaign. Since it became known that many persons with a previous response to a COVID-19 vaccination could safely receive a second dose, persons were referred to the allergy departments. In this study the aim was to identify persons at increased risk of reacting severely to a COVID-19 vaccination. If that is possible, more patients can be vaccinated outside the hospital and there is less need to refer to allergy departments in future.