Abstract
The Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) outbreak has caused massive damage to the global healthcare system and economy. To compete with the SARS-COV-2 pandemic, several vaccines have been proposed to immunize the population. The present study aimed to investigate the adverse effects following the three doses of COVID-19 vaccination, Pfizer (BioNTech), (Oxford-AstraZeneca (ChAdOx1 CoV-19), and Moderna among the adult population in the Eastern province of Saudi Arabia. In this study, the total number of participants were 426, among them 277 (65%) were females and 149 (35%) were males. An online survey using Google forms in the English language and translated into the Arabic language was used to record the information. The questionnaire was distributed to participants who received either Pfizer-BioNTech, Oxford-AstraZeneca or Moderna vaccines. The general characteristics of participants were obtained, alongside an evaluation of the vaccination's adverse effects. The results revealed that Pfizer-BioNTech COVID-19 vaccines caused significantly less adverse effects than Oxford-AstraZeneca (ChAdOx1) and Moderna (p < 0.001), and females experienced more adverse effects after vaccination compared to males. Injection site pain was the most common adverse event among the participants (60.6%), followed by fatigue, headache, and pain (43.9%), muscle and joint pain (32.4%), increased body temperature and shivering (24.2%). In addition, the group of individuals under the age of sixty was more likely to experience side effects than the participants with other age groups. All three vaccines, Pfizer-BioNTech, Oxford-AstraZeneca (ChAdOx1 CoV-19) and Moderna, cause post-vaccinal adverse effects; however, Moderna and Oxford-AstraZeneca (ChAdOx1) causes adverse effects more frequently than the Pfizer-BioNTech.