Abstract
The coronavirus disease 2019 (COVID-19) pandemic, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in numerous deaths worldwide, along with devastating economic disruptions, and has posed unprecedented challenges to healthcare systems around the world. In the wake of COVID-19's emergence in 2019, a variety of vaccine technologies were formulated and developed, including those that drew from the technology employed in messenger RNA (mRNA) vaccines, designed to curb the disease's transmission and manage the pandemic. mRNA vaccine has several advantages over traditional ones, and hence its development has received considerable attention recently. Researchers believe the mRNA vaccine technology will emerge as the leading technology because it is potent, inexpensive, rapidly developed, and safe. This article provides an overview of mRNA vaccines with a special focus on the efficacy and safety of the Moderna and Pfizer-BioNTech mRNA vaccines against the different variants of COVID-19 and compare them with the Oxford-AstraZeneca (viral vector) and Sinopharm (inactivated virus) vaccines. The clinical data reviewed in this article demonstrate that the currently authorized Moderna and Pfizer-BioNTech mRNA vaccines are highly safe and potent against different variants of COVID-19, especially in comparison with Oxford-AstraZeneca (viral vector) and Sinopharm (inactivated virus) vaccines.