UNDERSTANDING COVID-19 VACCINES: MECHANISMS, EFFICACY, AND SAFETY

Abstract

It has been over a year since SARS-CoV-2 was first reported in December of 2019 in Wuhan, China. To curb the spread of the virus, many therapies and cures have been tested and developed, most notably mRNA and DNA vaccines. Federal health agencies have approved emergency usage of these S gene-based vaccines with the intention of minimizing any further loss of lives and infections. Unfortunately, SARS-CoV-2 continues to mutate with new strains, such as the delta and omicron variants, which take on different and more contagious forms. Currently, some approved vaccines have shown to be less efficacious against the new variants. Thus, it is crucial to assess which vaccines are the most efficacious by examining their effects on the immune system, and by providing considerations for new technological vaccine strategies in the future.

This paper provides an overview of the current SARS-CoV-2 vaccines with their mechanisms of action, current technologies utilized in manufacturing of the vaccines, and limitations in this new field with emerging data. Currently, there are 19 FDA approved or authorized emergency use vaccines worldwide. Six of these vaccines have been granted emergency use authorization (EUA) by the FDA including three mRNA vaccines, one replication-defective viral vector DNA vaccine, and two inactivated virus vaccines. Each different kind of vaccine utilizes a different approach to induce immune response against the SARS-CoV-2 spike (S) protein. All offered vaccines have demonstrated to be safe and efficacious in preventing severe disease and death. Although the most popular COVID-19 vaccines have been proven effective, time will be the main factor in dictating which vaccine will be able to best address mutations and future infection (Shahid, 2022).