Comprehensive Review of the Initial 11 WHO Emergency Use Listed COVID-19 Vaccine Candidates: Mechanisms, Efficacy, and Comparative Attributes for Safety and Well-Being

Abstract

Since December 2019, the world has witnessed a massive outbreak of a novel coronavirus Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which prompted cross-national collaboration to establish essential diagnostics, effective treatment protocols, and most importantly the design and development of suitable COVID-19 vaccine candidates. This effort has been fueled by collaborations among academic researchers, funding agencies, companies, and regulatory authorities. As a result, more than 242 vaccine candidates are currently under clinical trial, and nearly 50 vaccines have been approved in different countries. In this study, we conduct a comprehensive review of 11 vaccine candidates that have been granted Emergency Use Listing (EUL) by the World Health Organization (WHO). Our review summarizes the mode of synthesis, mechanism of action, approval authority, target age group, efficacy, merits, and gaps of these vaccine candidates. Additionally, we provide comparative attributes of these vaccine candidates to enhance understanding of safety and well-being.