Comparative Evaluation of Short-term Clinical Safety and Efficacy of COVID-19 Vaccines - Covishield and Covaxin

Abstract

Background: Many candidate vaccines against COVID-19 are competing for their clinical safety and efficacy but few have got approval from the competent authorities. However, people are still concerned about their use. Objectives: To assess the clinical safety of COVID-19 vaccines, Covishield and Covaxin using the incidence of self-reported and solicited local and systemic adverse events and efficacy by collecting data on the occurrence of confirmed COVID-19 infection after vaccination and to compare the clinical safety and efficacy of both the vaccines. Method: This study was conducted as an online survey using a self-administered questionnaire, among the individuals who were vaccinated in the months of February, March and April 2021. The participants were categorised into two groups, based on the type of vaccine they received as Covishield and Covaxin. The two groups did not differ in terms of age and gender. Results: The proportion of participants who had adverse events after the first dose of vaccination was significantly high with Covishield (37.2%) compared to Covaxin (17.4%). But the proportion of participants who developed adverse events after the second dose was not significantly different between Covishield and Covaxin (16.1% with Covishield and 23.8% with Covaxin). The incidence of COVID-19 infection after vaccination was similar in both the groups (4.5% in Covishield group and 5.7% in Covaxin group, p = 0.5, Chi-square test). Conclusion: The findings from this study gives real-world data that both Covishield and Covaxin are equally effective in preventing COVID-19 infection and have an acceptable safety profile.