Pfizer/BioNtech BNT162b2: adverse events and insights from an Australian mass vaccination clinic for COVID-19

Abstract

The Pfizer/BioNtech BNT162b2 is a major vaccine used in the Australian COVID-19 immunisation programme. We report on BNT162b2 safety in the observation period in a dedicated vaccination clinic linked to a quaternary teaching hospital. We performed a retrospective review of medical records for 57_842 vaccinations, and describe the model of care and adverse event rate at the clinic during its first_2 months of operation. A total of 243 adverse events following immunisation (0.42% of total vaccine doses) were recorded in the immediate observation period post-vaccination, which were predominantly immunisation stress-related responses. Of the 110 patients who experienced an adverse event with their first dose of the vaccine, 90% returned for their second dose of the vaccine, with 87% not reporting any further adverse reaction with the subsequent dose. Nineteen (0.03% of total doses) people were reviewed for an allergic reaction, of which 10 (53%) reported a history of prior allergies. A female predominance was present in both total adverse reactions (70%) and allergic vaccine reactions (79%). Only two patients experienced anaphylaxis (0.003% of total doses), in keeping with low rates of adverse reactions to the BNT162b2 vaccine in the current literature. Overall, the present study reinforces the safety of BNT162b2 in the Australian population, describes vaccination completion rates after adverse events and identifies predisposing factors for rare allergic reactions to the vaccine.