ABSTRACT
Several Phase-III clinical studies investigating vaccine safety and effectiveness have been published a year following the first breakout of the COVID-19 pandemic. These vaccine candidates were produced using a variety of vaccination technologies, including mRNA, recombinant protein, adenoviral vector, and inactivated virus-based platforms, by various research organizations and pharmaceutical firms. Despite many successful clinical studies, participants are restricted by trial inclusion and exclusion criteria, geographic location, and the current state of the virus epidemic. Many concerns remain, particularly for specific populations such as the elderly, women who are pregnant or nursing, and teenagers. Vaccine effectiveness against asymptomatic infection and particular viral variations, on the other hand, is still largely unclear. This review will focus on vaccination candidates that have completed Phase-III clinical trials and will examine the scientific evidence that has been gathered so far for these vaccine candidates for various subgroups of individuals and virus variations.