Assessment of adverse events following vaccination with AstraZeneca Coronavirus Disease 2019 vaccine in Greater Kampala, Uganda, March-April 2021

Abstract

Background Tracking of adverse events following vaccination is important for evaluating vaccine safety. During March 2021, Uganda began COVID-19 vaccination using the Astra-Zeneca vaccine targeting teachers, health workers, security personnel, and the elderly. We assessed adverse events following AstraZeneca vaccination in Greater Kampala, Uganda to track the safety of the vaccine. Methods We used vaccination registers to identify persons who received ≥ 1 dose of the AstraZeneca COVID-19 vaccine during March 10–April 30, 2021. Adverse events following vaccination were defined as an untoward medical occurrence after vaccination (not necessarily causally related to the vaccine). Serious adverse events were defined as any event considered life-threatening, resulting in hospitalization, persistent disability ˃28 days, death, or congenital anomaly. We extracted telephone contacts for a systematic random sample of vaccinated individuals and their next of kin where necessary. We then conducted phone interviews to collect data on demographics and details of adverse events where they occurred. We used logistic regression analysis to establish relationships between variables and our outcome of interest (developing an adverse event following vaccination). Results Among 374 subjects interviewed, mean age was 41 years; range 20–85 years; 176 (47%) were female. Of these, 235 (63%) received only one dose and 139 (37%) received two doses. In total, 516 adverse events occurred in 286 (77%) individuals, including in 255 (68%) individuals after the first dose and in 45 (32%) individuals after the second. The most common adverse events were redness/pain/itching at the injection site (34%) and headache (32%). None of the events were classified as serious. Persons aged 20–29 years (AOR 4.7; 95% CI: 2.0–10.2), 30–39 years (AOR 3.7; 95% CI: 1.8–7.4) and 40–49 years (AOR 2.8; 95% CI 1.3–5.0) were more likely to develop adverse events than those aged ≥ 50 years. Conclusion Most individuals experienced ≥ 1 adverse event. No serious adverse events were reported. Younger age (˂50 years) was associated with adverse event. We recommend use of the AstraZeneca COVID-19 vaccine in Uganda based on its safety.