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.

Analysis of immunization time, amplitude, and adverse events of seven different vaccines against SARS-CoV-2 across four different countries

“…For most patients, at least one AEFI occurred with all types of vaccines during the first 24 hrs. after injection, and most of them qualified the symptoms as “very mild” or “mild” both after the first and second dose, except for mRNA-1273 for which nearly half of the volunteers reported moderate symptoms after the second dose as reported previously ( 19 , 20 , 28 , 30 – 34 ).…”

Analysis of immunization time, amplitude, and adverse events of seven different vaccines against SARS-CoV-2 across four different countries

“…For most patients, at least one AEFI occurred with all types of vaccines during the first 24 hrs. after injection, and most of them qualified the symptoms as “very mild” or “mild” both after the first and second dose, except for mRNA-1273 for which nearly half of the volunteers reported moderate symptoms after the second dose as reported previously(18,20,22–27).…”

Heterologous booster vaccination with CoronaVac following prime vaccination with mRNA vaccine

“…The SFB assay was performed as previously described. 28 , 29 Cells, expressing the spike protein of either WT, Delta or Omicron variants, were seeded at 1.5 × 10 5 cells/well in 96‐well V‐bottom plates (ThermoFisher Scientific, Waltham, USA). Cells were incubated with human serum (diluted 1:100 in 10% FBS; HyClone, Chicago, USA) followed by a secondary incubation with a double stain, comprising Alexa Fluor 647‐conjugated anti‐human IgG (1:500 dilution; ThermoFisher Scientific) and propidium iodide (PI; 1:2500 dilution; Sigma Aldrich, Burlington, USA).…”

“…After 48 h, cells were lysed and luciferase activity was quantified on a GloMax Luminometer (Promega, Madison, USA). For samples that do not exhibit 50% inhibition at the lowest dilution tested, 5 we report the IC50 as a value of ½ LOD (the limit of detection). A subset of age‐matched samples was randomly selected and examined ( n = 54 for CV day 90; n = 32 for mRNA group day 90) because of limited sample availability.…”

“…4 Despite the huge success of COVID-19 mRNA vaccines, mild or severe adverse effects, including pain, local redness or swelling, fever, fatigue, headache, muscle pain, nausea, vomiting, itching and chills, are common. [5][6][7] More severe hypersensitivity reactions are uncommon, with anaphylaxis reported in 2.5-11.1 cases per million doses. 8 Overall, hypersensitivity-related adverse events have been reported in 0.63% of individuals who received BNT162b2 and 1.5% of individuals who received mRNA-1273, compared with 0.51% and 1.1%, respectively, in the placebo groups.…”