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Soe, Phyu Mar

University of British Columbia

Post-marketing surveillance is important for COVID-19 vaccines following initial emergency approval, particularly for populations not included in pre-approval studies. This dissertation characterizes the safety of mRNA COVID-19 vaccines using post-approval surveillance data in three distinct groups: older adults (≥65 years), pediatric populations (<20 years), and individuals with autoimmune diseases. Additionally, it examines the impact of different recruitment methods on participation rates in vaccine safety surveys. Data were sourced from the Canadian National Vaccine Safety Network (CANVAS) during the pandemic and included both vaccinated and unvaccinated individuals from seven Canadian provinces and territories. The outcomes of interest were health events that prevented daily activities, resulted in school/work absenteeism, or required medical consultation. Analyses profiled adverse events and adverse events of special interest (AESIs) following each mRNA COVID-19 vaccine product and dose, and evaluated health events associated with vaccination. Among the different recruitment methods used in the CANVAS active surveillance study, technology-assisted recruitment through vaccine registries proved the most effective in reaching and retaining a large, diverse sample. Across all study populations, the most frequently reported symptoms following any dose of mRNA COVID vaccine were local and systemic symptoms, such as feeling unwell, fever, and headache, and most were self-limited and resolved within seven days. Vaccinated older adults and adolescents reported a higher frequency of health events within seven days after the second mRNA COVID-19 vaccine dose (limited to mRNA-1273 for older adults) compared to their unvaccinated counterparts. Emergency care utilization among vaccinated individuals within seven months after the first dose was similar to or lower than among unvaccinated individuals. Among individuals with autoimmune diseases, the frequency of health events was similar within a week following the co-administration of COVID-19 and influenza vaccines and the administration of the COVID-19 vaccine alone, indicating no additional risk from co-administration. This dissertation provides important evidence on the safety profiles of mRNA COVID-19 vaccines, offering valuable insights to inform vaccination policies in Canada and globally. These findings support effective communication about COVID-19 vaccine safety, helping vulnerable populations make informed decisions.

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2025-04-25

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/90820

Population and Public Health

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/