Safety and Reactogenicity of the ChAdOx1 (AZD1222) COVID-19 Vaccine in Saudi Arabia

Introduction: The Kingdom of Saudi Arabia was one of the first countries to implement a COVID-19 vaccination program. This study estimated the safety and reactogenicity of the ChAdOx1-S vaccine after the first dose administered to adults. Methods: This cross-sectional study included 1592 randomly selected vaccinees from April to May 2021. A questionnaire was delivered to the vaccinees via phone calls 7 and 21 days after the first vaccine dose. Results: Of the 1592 vaccinees who had the first dose, the mean age was 37.4 (+/- 9.6) years and 81% were males. Of all the vaccinees, 553 (34.7%) reported an adverse reaction on the first telephone call. The most common symptoms were: pain at the site of injection (485, 30.5%), musculoskeletal symptoms (438, 27.5%), skin rash (307, 19.2%), gastrointestinal symptoms (379, 23.8%) and fever (498, 31.3%). Men were more likely to report fever (76.9% vs. 23.1%; P = 0.005), skin rash (81.1% vs. 18.9%, P = 0.005) and pain at the injection site (77.3% vs. 22.7%, P < 0.0001). Post-vaccine COVID-19 infection was 0.5% and there were no hospitalizations. Conclusion: This study observed no major side effects of the ChAdOx1-S vaccine and no reported breakthrough infection during the observation period. (C) 2021 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.

Automated summary

This study evaluated the safety and reactogenicity of the ChAdOx1-S vaccine after the first dose in 1592 adults, finding that males were more likely to experience adverse reactions such as fever, skin rash, and pain at the injection site. The study also showed no breakthrough infections of the ChAdOx1-S vaccine during the observation period.