COVID-19 Vaccines and Emergency Use Authorizations

Recently, the U.S. Food and Drug Administration approved the use of updated COVID-19 vaccines formulated to target variants of the virus that are currently circulating. Included in the Emergency Use Authorization are mRNA vaccines for 2023-2024 from ModernaTX Inc. and Pfizer Inc., as well as the Novavax COVID-19 Vaccine, Adjuvanted. These updated vaccine formulations provide better protection against newer strains of the virus than previous formulations and help prevent serious consequences of COVID-19 infections, such as hospitalization and death.

How are vaccines tested?

All vaccines are required to go through three phases of clinical development before FDA approval. Phase 1 involves small groups of people (20-100 individuals) receiving the trial vaccine while researchers gather information about the vaccine’s efficacy and any side effects. Phase 2 expands the clinical trial to hundreds of trial participants of varying demographic backgrounds, which provides additional safety information on side effects and risks. Phase 3 includes thousands of trial participants. This phase allows researchers to confirm the efficacy of the vaccine and to monitor side effects and their varying levels of commonality. After all three phases have been completed, the FDA reviews the data and approves the vaccine for use in the general population if they determine that the benefits of the vaccine outweigh the potential risks of contracting the disease that it helps prevent or mitigate. A fourth phase takes place after approval, which evaluates the vaccine’s safety and effectiveness over a longer period of time.

What is an Emergency Use Authorization?

Vaccines approved under an Emergency Use Authorization (EUA), like COVID-19 vaccines, go through the same testing process as any other vaccine. An EUA is used to speed up the clinical development process. All three phases are still completed before the FDA approves the vaccine for use, but the trial phases may be overlapped. According to data from the CDC and other sources, all available COVID-19 vaccines are safe for use and the risk of any possible side effects has been shown to be less severe than the potential risks of contracting COVID-19 without prior vaccination. The CDC recommends that children and adults ages 6 months and older receive an updated vaccine.