The Current Position of COVID-19 mRNA Vaccines in the US

In the dire face of the COVID-19 pandemic, many biotech companies took flight and immediately went into development of SARS-CoV-2 vaccines. Over time some of these companies have moved faster through clinical trials and have secured government sponsorships to help bring the vaccines faster to market. As a result, the US currently has several vaccines in phase III trials. Of these vaccines, many are of a new class: mRNA vaccines. By encoding different viral proteins in mRNA, the host can transcribe and produce the protein which the body’s immune system can use to prepare to fight the virus by recognizing key components without ever seeing the full active virus.

The SARS-CoV-2 vaccine trials are unique as they have pushed through phase II trials faster than on average. In phase III trials, a large number of participants are needed for each trial (~30,000). While these participants numbers can include sites in foreign countries, many US based companies face challenges in conducting international trials. That leaves a majority of participants to consist of US based populations. There are two main mRNA vaccine candidates that the US government is currently supporting: Moderna mRNA-1273 and Biontech/Pfizer’s BNT162b2 (There are other vaccines candidates as well that use different mechanisms). At this time, these two vaccines are the furthest along in the mRNA pipeline, both currently in phase III.

The Moderna mRNA-1273 vaccine has been one of the fastest vaccines developed in response to COVID-19. By encoding the entire spike protein as mRNA, the vaccine uses host cells to produce the spike protein thus leaving the vaccine without any viral proteins. Moderna acquired an early government funding source on August 11th through the NIH at $1.5 billion for 100 million doses, putting each dose at $15. With the US population at ~328.2 million, there is a need for more than 100 million doses. However, manufacturing a large number of doses of a single vaccine is risky, and instead the government has multiple contracts with different vaccine manufacturers to work towards covering the US population total.

Biontech and Pfizer’s BNT162b2 and BNT162b1 vaccine are both also at the forefront of vaccine response and respectively encode the entire spike and the receptor binding domain (RBD) of the spike as mRNA. After initial review, the BNT162b2 outperformed the BNT162b1 vaccine and was the candidate they chose to push forward into phase III trials. 

Right now, we are at an unprecedented point in vaccine development history. The large number of vaccine candidates could bring about competition for the highest efficacy vaccine to bring the best results to market. However, as the world grows more desperate to go back to normal will speed take precedence over efficacy?