Multiple battles are being fought in the war against the SARS-CoV-2 coronavirus that causes COVID-19. Currently, there are nearly 5,000 clinical trials listed in the World Health Organization (WHO) database, either underway or in the recruiting stage, for vaccines and antiviral drugs. The Moderna mRNA vaccine and Janssen vaccine have received emergency use authorization (EUA) from the Food and Drug Administration (FDA); the Pfizer-BioNTech Vaccine (marketed as Comiraty) received FDA approval in August 2021.
Both the Moderna vaccine and Comiraty are mRNA-based, as opposed to most conventional vaccines against established diseases that are protein-based. Typically, the key ingredient in viral vaccines is either part of an inactivated virus, or one or more expressed proteins (antigens) that are a part of the virus. These protein antigens are responsible for eliciting an immune response that will fight future infection by the actual virus. Another approach is to use a replication-deficient viral vector (such as adenovirus) to deliver the gene encoding the antigen into human cells. This method was used for the coronavirus vaccine developed by Oxford University in collaboration with AstraZeneca; phase 3 interim data were announced on the heels of the Pfizer/BioNTech and Moderna announcements. All three vaccines target the SARS-CoV-2 spike protein, because it is the key that unlocks a path of entry into the host cell.Continue reading “mRNA Vaccines for COVID-19: The Promise and Pitfalls”