ABSTRACT
The frequency of reported symptoms was higher in: the younger (<40 years) age group, those who had taken two doses, and participants with a history of adverse reaction to a medicine/vaccine. Keywords: Nigeria * COVID-19 * Oxford-AstraZeneca * ChAdOx1 nCoV-19 * Adverse effects * Vaccine Introduction The widespread morbidity and mortality associated with the 2020 COVID-19 pandemic precipitated the most extensive and rapid global vaccine development program in history, culminating in several vaccine candidates attaining phase 3 efficacy milestones and receiving emergency use authorization by the end of the same year [1,2]. Using a confidence interval of 95%, a 6% margin for error, and allowing for 10% no-response rate, the minimum sample size was determined to be 296 by Cochran formular. Ethical approval This study was approved by the Health Research Ethics Committee of Bingham University Teaching Hospital, Jos, Plateau State.