COVID-19 vaccine provocation test outcome in high-risk allergic patients: A retrospective study from a tertiary hospital in Indonesia

Background: High COVID-19 vaccine coverage is essential. Patients who are considered high risk for hypersensitivity reactions and have had an allergic reaction to the COVID-19 vaccine are usually referred to an allergist for assessment of vaccination. Administration of a vaccine graded challenge (also known as a provocation test) is an option that can be considered in this population. This primary objective of this study is to describe the outcome of the COVID-19 vaccine provocation test and to understand the predicting factors associated with hypersensitivity reaction after the provocation test as the secondary objective.

Methods: Adult patients with a history of hypersensitivity reaction to the first COVID-19 vaccine and high-allergic patients who underwent COVID-19 vaccine provocation test up until May 2022 were included. A protocol using skin prick test (SPT), intradermal test (IDT), followed by graded challenge was developed for the determined vaccine used.

Results: A total of 232 patients were included in the analysis. Twenty-eight had hypersensitivity to their first COVID-19 vaccine dose and 204 were high risk for allergic reaction. Hypersensitivity reactions occurred in 20 patients (8.6%, 95% CI: 5-12.2%), consisting of 4 reactions after SPT, 9 after IDT, 7 during or after titrated challenge. Half of the reactions were mild; however, 3 patients developed severe reactions. Patients with history of anaphylaxis were more likely to experience hypersensitivity reaction after provocation test (aRR = 2.79, 95% CI: 1.05-7.42).

Conclusion: Provocation test in COVID-19 vaccination has a high success rate in patients with a history of hypersensitivity to the first COVID-19 vaccine and in high allergic patients. History of anaphylaxis is associated with hypersensitivity reaction after a COVID-19 vaccine provocation test.