The FDA has backed away and revoked a number of Emergency Use Authorizations (EUAs) that it had issued in the past, including those for hydroxychloroquine and a multitude of less-than-accurate COVID‑19 tests. By all accounts, there is a degree of trepidation in the scientific community that many of the Agency’s decisions regarding EUAs are being guided by politics rather than science. With these stumbles in the past, clearly the concern that a COVID-19 vaccine that is permitted use prior to full approval could come at a great cost to the reputation of the FDA as well as the public health of the nation—especially if an EUA is issued prior to completion and evaluation of the pivotal Phase 3 trials.
While early reports appear to confirm that the vaccines tested thus far in Phase 1 and Phase 2 studies appear to be safe, the efficacy of the different products has not yet been established. There are questions, such as: What percentage of the study participants will develop a sufficient level of neutralizing antibodies? How many injections will be needed, at what dose, and at what optimal time between vaccinations? How long will the antibodies persist at a level that will impart immunity and protect patients from future infection, and how long will that immunity last? Will the potential for antibody-dependent enhancement of infectivity be recognizable (if interested see Nature 584, p 353-363)? In addition, if a vaccine is released prior to these questions being answered and does not provide adequate protection from infection, can people who have received one vaccine be safely vaccinated with another and will the second vaccine be safe and efficacious? How will multiple vaccinations be tolerated?
While this is a deadly virus and any action to subdue it will be a move in the right direction, making a move too soon could make it difficult, if not impossible, to recruit subjects for other vaccines or therapeutics under development. Imagine a vaccination program kicked off with 100s of millions of doses administered to find that the product did not work as anticipated. Imagine the resources that would be depleted, for instance syringes, vials, and alcohol swabs, as well as human resources that would be required, just to start over again with the next product. Will the medical community and manufacturers of products and components be able to react to an increased demand?
We all hope that any FDA decision will be based strictly on the science and dictated by the data. Jumping the gun without sufficient data could be like shooting blanks at the enemy.