As part of Bara’ Abdallah AlShurman’s doctoral research exploring the multifactorial and evolving nature of COVID-19 vaccine hesitancy among university students in Ontario, Canada, two studies were recently published in Vaccine.
The first published paper presents a psychometric validation of a COVID-19 Vaccine Hesitancy Scale designed to assess hesitancy toward both primary and booster doses, offering insight into how vaccine hesitancy shifts across different stages of the vaccine rollout. The second published paper investigates changes in vaccine hesitancy over time and identifies the psychological, social, and contextual factors that influence these shifts within the University of Waterloo student population.
Bara’ received invaluable support from the Statistical Consulting and Survey Research Unit (SCSRU) at the University of Waterloo. In the early stages of the project, the SCSRU provided feedback on the questionnaire design and item clarity, which helped refine the survey prior to launch. In the psychometric validation study, statistical guidance was sought particularly from the senior consultant “Joslin Goh” to address missing data, incorporate sampling weights, and determine the most appropriate reliability and validity testing techniques.Throughout the collaboration, various models were explored, including complete case analysis versus imputed data using the Expectation-Maximization technique, and psychometric evaluations conducted both with and without sampling weights. Exploratory and confirmatory factor analyses were used to examine how scale items loaded onto factors, and model fit was improved by covarying error terms.
In the second study, the consultation helped determine the best regression strategy for modeling non-normally distributed count data (vaccine hesitancy scores) measured at two time points. Several models including linear, logistic, and binomial regression were tested and compared using diagnostic tests and residual plots. Ultimately, Bara’ and the consultation team (Joslin Goh and Xisi Zhang) selected a Generalized Estimating Equations (GEE) model with binomial distribution as the most suitable approach. To identify the most robust predictors of change in vaccine hesitancy, variables were iteratively refined using the Quasi-likelihood under the Independence Model Criterion (QIC). This collaborative process played a key role in enhancing the methodological rigour of both publications.
This collaborative work involved Bara’ Abdallah AlShurman (School of Public Health Sciences), Zahid Ahmad Butt (School of Public Health Sciences), Shannon Majowicz (School of Public Health Sciences), Kelly Grindrod (School of Pharmacy), Joslin Goh (Statistics and Actuarial Science), Xisi Zhang (in the 2nd paper) (Statistics and Actuarial Science).
Bara’ Abdallah AlShurman is a fifth-year PhD candidate in the School of Public Health Sciences, specializing in Epidemiology and Biostatistics. Her research focuses on vaccine hesitancy, vaccination behaviour, COVID-19, infectious diseases, syndemics, young adults, and marginalized populations.
Links to published papers:
Psychometric validation of the COVID-19 vaccine hesitancy scale for primary and booster doses among university students: A cross-sectional study (peer-reviewed publication)
Understanding the shift in COVID-19 vaccine hesitancy and its associated factors for primary and booster doses among university students: A cross-sectional study (peer-reviewed publication)