Post-Emergency Use Authorization Active Safety Surveillance Study among Individuals in the Veteran’s Affairs Health System Receiving Pfizer BioNTech Coronavirus Disease 2019 (COVID 19) Vaccine

Study type

• Study type:
  Non-interventional study
• Scope of the study:
  Assessment of risk minimisation measure implementation or effectiveness

  Disease epidemiology

  Drug utilisation

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Anatomical Therapeutic Chemical (ATC) code:
  (J07BX03) covid-19 vaccines

  covid-19 vaccines
• Medical condition to be studied:
  COVID-19 immunisation

Population studied

• Age groups:
  • Paediatric Population (< 18 years)

    • Infants and toddlers (28 days – 23 months)
    • Children (2 to < 12 years)
    • Adolescents (12 to < 18 years)
  • Adult and elderly population (≥18 years)

    • Adults (18 to < 65 years)

      • Adults (18 to < 46 years)
      • Adults (46 to < 65 years)
    • Elderly (≥ 65 years)

      • Adults (65 to < 75 years)
      • Adults (75 to < 85 years)
      • Adults (85 years and over)
• Special population of interest:
  Immunocompromised
• Estimated number of subjects:
  107458

Study design details

• Main study objective:
  To assess whether the following groups of individuals in the VHA system experience increased risk of safety events of interest following receipt of the Pfizer-BioNTech COVID-19 vaccine: individuals receiving first dose, individuals receiving the primary series of two doses, individuals receiving additional approved doses of the Pfizer-BioNTech COVID-19 vaccine after the primary series of two doses
• Outcomes:
  Risk of safety events of interest following receipt of the Pfizer-BioNTech COVID-19 vaccine among various groups of individuals and sub-cohorts of interest in the VHA system, The proportion of individuals receiving at least one dose of the the Pfizer-BioNTech COVID-19 vaccine, 2-dose vaccine completion rate, additional approved dose(s) completion rate, distribution of time gaps between the first and second dose and between the second and additional approved dose(s), and demographics and health histories of recipients, overall and among the subcohorts of interest
• Data analysis plan:
  A stepwise approach will be performed for signal detection, evaluation, and verification. Signal detection: The maximized sequential probability ratio test (MaxSPRT) using a binomial probability model will be applied to the self-controlled risk interval (SCRI) analysis and the Poisson-based MaxSPRT to the comparison group. Signals will be detected if the critical values are reached via the SCRI or active comparator analysis. Signal evaluation: Detected signals will be confirmed through quality assurance and multivariate adjustment using Poisson regression to account for differences between vaccinated and active comparator cohorts. SCRI and self-controlled case series analyses will be conducted as well as a comparison to contemporary unvaccinated controls. Signal verification: Diagnostic validation of the detected safety events of interest via adjudication of medical records by VHA clinicians for outcome verification will be conducted in a representative sample of cases.