Late last week, the U.S. Food and Drug Administration issued the first Emergency Use Authorization (EUA) for a COVID-19 vaccine in the United States. The vaccine is manufactured by Pfizer Inc. and BioNTech SE. It consists of two doses taken three weeks apart, and is indicated for use in individuals 16 years of age and older.
The official authorization follows Thursday’s meeting of FDA’s Vaccines and Related Biological Products Advisory Committee to review and discuss information about the vaccine. The external advisory panel voted to recommend that FDA grant authorization, agreeing that the benefits of the vaccine outweigh its risks for use. While it did not ultimately have to follow the Committee’s recommendation, FDA officially did so on Friday.
Emergency Use Authorization
An EUA grants FDA “authorization,” which is not the same as FDA “approval.” Vaccines are typically approved though a biologics license application, which can require years of clinical testing and back-and-forth with regulatory authorities. FDA uses this pathway to ensure that products meet a certain standard of safety and effectiveness. The EUA application and review are an abbreviated authorization process that only requires a showing that the product’s benefits outweigh its risks.
EUAs have already issued for a variety of products like test kits, face masks, ventilators, and other drugs and devices used during the COVID-19 pandemic. Although the EUA process is not new, this is the first time that FDA is authorizing a vaccine product through the expedited EUA pathway. Drug and biologic products pose greater risks than diagnostics and PPE, and require clinical data to evaluate safety and effectiveness. While authorization was granted for the vaccine, a recurring issue in Thursday’s committee meeting was the additional information and data FDA may want from Pfizer as the vaccine moves from authorization to full approval through a BLA.
The First of Its Kind
In addition to being the first vaccine to be granted EUA, the Pfizer/BioNTech vaccine is also the first mRNA vaccine ever to be made available for mass inoculation. Unlike most vaccines, which use weakened or inactivated pathogens to trigger an immune response in the recipient, the Pfizer/BioNTech COVID-19 vaccine contains temporary genetic material (mRNA) that codes for the spike protein found on the surface of the novel coronavirus. Once the vaccine is administered, cells in the recipient’s body take up the mRNA and temporarily produce and display this same spike protein on their surfaces until the mRNA is degraded. The body’s immune system recognizes the spike protein as foreign and starts making antibodies. Thus, if the vaccine recipient were exposed to the coronavirus in future, the body would already know how to mount the appropriate immune response before the recipient developed symptoms.
Though this is the first time an mRNA vaccine has been authorized for use on the general public, FDA has emphasized that these vaccines will be held to the same standards of safety and efficacy as any other type of vaccine. To that end, in the briefing document provided ahead of the December 10 meeting, VRBPAC reported an extensive body of data relating to Pfizer/BioNTech’s ongoing phase-3 randomized, double-blinded, and placebo-controlled trial of the vaccine in approximately 44,000 participants. These data played a key role in informing the committee’s decision to recommend authorization of the vaccine.
There was significant discussion in Thursday’s Advisory Committee meeting around potentially contraindicated populations in light of two adverse events in vaccine recipients with known allergies to medications. It appears that FDA has worked with Pfizer to draft suitable warning language and contraindications for that population. The CDC stated on a conference call Sunday that people with a history of severe allergic reactions can still take the Pfizer/BioNTech vaccine, but recommends that they discuss the risks of doing so with a doctor and be monitored for 30 minutes following administration.
The Committee also focused on the indicated age group for the vaccine. Younger populations are known to contract COVID-19 at lower rates and to not experience symptoms as severely as other groups, limiting the benefit of approving the vaccine for those groups. FDA ultimately authorized the vaccine for use by people aged 16 years and older. Since the authorization, CDC’s Advisory Committee on Immunization Practices (ACIP) has also recommended the vaccine for use in this population.
Although the vaccine has been authorized for use in the U.S., safety monitoring is an ongoing concern. FDA has, in the case of hydroxychloroquine, revoked an EUA following serious adverse events and questionable efficacy data. As a condition of authorization, Pfizer must report serious adverse events associated with the vaccine to the Vaccine Adverse Event Reporting System.
The vaccine will likely be distributed according to CDC’s guidance that health care personnel and long-term care facility residents be vaccinated in the initial phase. While not included in the initial phase, ACIP also identified older individuals and those with underlying medical conditions as potential future priority groups. To prepare for the vaccine rollout, CDC has compiled clinical information and training resources and recommended that all health care personnel administering vaccines receive comprehensive competency-based training on vaccine policies and procedures.
VRBPAC will hold another meeting this week to discuss the EUA application for a second COVID-19 vaccine submitted by Moderna, Inc.