The Race for COVID-19 Vaccines: The Various Types and Their Strengths and Weaknesses

SARS-CoV-2 causes the highly contagious coronavirus disease (COVID-19), first discovered in Wuhan, China, in December of 2019. As of August 21, 2021, over 211 million people have been diagnosed with COVID-19 and 4.42 million people have died from the disease worldwide. The COVID-19 pandemic has adversely affected world economies, global public health infrastructure, and social behaviors. Despite physical distancing and the advent of symptomatic and monoclonal antibody therapies, perhaps the most effective method to combat COVID-19 remains the creation of immunity through vaccines. Scientific communities globally have been diligently working to develop vaccines since the start of the pandemic. Though a few have been authorized for use, the Pfizer vaccine was the first to be given full approval in the United States in August 2021 – being the quickest vaccine to ever be developed. Although several vaccines produced via different approaches are in use, no mortality has been reported thus far from vaccine use. Here, we highlight the latest advances in the development of the COVID-19 vaccines, specifically the lead candidates that are in late-stage clinical trials or authorized for emergency use. As SARS-CoV-2 uses its spike protein to enter a host cell and cause infection, most vaccine candidates target this protein. This review describes the various COVID-19 vaccines - authorized and/or under development - and their composition, advantages, and potential limitations as the world continues to fight this devastating pandemic.