Adverse events following first dose of ChAdOxI nCoV-19 (Covishield) among health care workers in Sri Lanka

Abstract

Introduction: A community vaccination programme is crucial to combat COVID-19 pandemic. An independent post-vaccine surveillance is important to identify adverse events following immunization (AEFI) in the population. Objective: To estimate the prevalence of AEFI after covishield vaccination among all categories of health care workers (HCWs) after the first dose. Methods: A multicentred cross-sectional survey was conducted in six provinces. A self-administered questionnaire was used to gather demographic data and AEFI. Results: Of 5140, 67.8% were females. The mean (SD) age was 40.69 (±10.07) years. At least one comorbidity was reported in 15.4%, At least one AEFI was reported in 86.6% and 49.3% had local AEFI. Bodyaches(54.4%), headaches (57.3%), fever (58.4%), chills(51.2%)( fatigue(37.5%) and arthralgia (36%) were the most reported systemic AEFI. Majority lasted <24 hours. Pain and redness at the site were the most reported local AEFI. Mean duration of onset of fever and site of pain was 6.65 and 9.67 hours respectively. The population was divided into two groups according to the mean age; <40 and >40 years and, study parameters were compared. Most of the systemic (fever, nausea, fatigue, itching) and all local AEFI were significantly higher among the <40-year-old group. Reactions occurred within first 20 minutes in 2%. Anaphylaxes developed in 12 patients. History of an叩hylaxis, drug, or food allergies were reported in 0.6%, 2.8%, 6.7% respectively, they didn't show significant relation to current vaccine induced allergies or anaphylaxis. Despite having minor AEFI, 71.1% attended routine work while 0.2% were hospitalised and treated.