Abstract
Prior research using electronic health records for Covid-19 vaccine safety monitoring typically focuses on specific disease groups and excludes individuals with multimorbidity, defined as ≥2 chronic conditions. We examine the potential additional risk of adverse events 28 days after the first dose of CoronaVac or Comirnaty imposed by multimorbidity. Using a territory-wide public healthcare database with population-based vaccination records in Hong Kong, we analyze a retrospective cohort of patients with chronic conditions. Thirty adverse events of special interest according to the World Health Organization are examined. In total, 883,416 patients are included and 2,807 (0.3%) develop adverse events. Results suggest vaccinated patients have lower risks of adverse events than unvaccinated individuals, multimorbidity is associated with increased risks regardless of vaccination, and the association of vaccination with adverse events is not modified by multimorbidity. To conclude, we find no evidence that multimorbidity imposes extra risks of adverse events following Covid-19 vaccination.
Highlights
Prior research using electronic health records for Covid-19 vaccine safety monitoring typically focuses on specific disease groups and excludes individuals with multimorbidity, defined as ≥2 chronic conditions
This study aims to examine the relationship between the first dose of Covid-19 vaccination and adverse events of special interest (AESI) among patients with chronic disease in Hong Kong and the potential additional AESI risk following vaccination associated with multimorbidity
We found no evidence of a modified association between vaccination and AESI among those living with multimorbidity compared with those without in general
Summary
Prior research using electronic health records for Covid-19 vaccine safety monitoring typically focuses on specific disease groups and excludes individuals with multimorbidity, defined as ≥2 chronic conditions. There have been widespread speculations of cardiovascular and other adverse events of special interest (AESI) in relation to Covid-19 vaccines[2,3] This may be due to thromboembolic safety signals[4,5] and case reports of other adverse outcomes, such as Bell’s palsy[6,7] and myocarditis[8,9] following the administration of specific vaccines. Previous research before the pandemic has shown a potential risk increase of cardiovascular events and other adverse outcomes in people living with multimorbidity compared with those without[16,17]. This study aims to examine the relationship between the first dose of Covid-19 vaccination and AESI among patients with chronic disease in Hong Kong and the potential additional AESI risk following vaccination associated with multimorbidity
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