With attention firmly focused on the COVID-19 vaccine rollout in the United States, a key point in the process has been largely overlooked: full approval of the vaccines themselves. The vaccines currently being distributed and administered across the U.S. are still approved only under the U.S. Food and Drug Administration’s (FDA) Emergency Use Authorization. Full vaccine approval normally takes five to ten years. But rumor has it that FDA approval for COVID vaccines may come as early as this year.
The approval process gives the FDA an opportunity to ensure we have the long-term data needed to make use of the vaccines as a tool to stem the pandemic. While some hold out hope that mass vaccination alone will bring an end to the pandemic, from what we know today about the virus and its ability to mutate and evolve, there’s no guarantee it will. With the approval process, the FDA can move us closer to that goal.
There are some pieces of data that we will definitely have access to through the FDA approval process. We now have roughly eight months of clinical trial data on some of the vaccines, including real-world data since distribution began. The approval process will likely give us access to the data showing, over the course of the full eight months, whether the vaccines provide robust protection from infection or from serious or severe disease. We’ll also receive more definitive evidence about the safety of the vaccines which, at least so far, do not seem to be causing major, widespread concerns.
But the FDA can go much further as they consider full approval for the vaccines, and ask the vaccine makers to provide more information about other aspects of how the vaccines are performing.
First, we need to dig into the details of vaccine efficacy and the durability of the protection it affords us. The antibodies to even the best of the vaccines will no doubt fade over time, but to what extent? Do the levels of neutralizing antibodies generated in response to the vaccines drop quickly or slowly and at what point does it fade away entirely? And what of the T cell response and how it may change over a period of one, two or five years? Will we need booster shots or to be revaccinated every year? A more technical question that the FDA can help us answer is whether adenovirus vector vaccines, if proven effective against initial infection, can be used as boosters or for revaccination if needed.
Possibly the biggest question that the FDA could help us answer is around the effectiveness of vaccines against variants of the virus. We already know that variants can be more transmissible and that some are also more lethal and better able to evade our immune protections. We can also assume that as our immune protection from a vaccine fades over time, we may be more susceptible to infection by the variants. In addition to asking companies to provide data on known variants, the FDA can ask them to collect and share data on the vaccine’s efficacy against new variants, as they appear.
The final question the FDA can ask the companies to answer is whether the vaccines can stop the pandemic by inhibiting both infection and transmission. While it’s tempting to believe that an effective vaccine automatically prevents further transmission of a virus, the truth is that not all vaccines can manage both sides of the equation.
For example, the inactivated polio vaccine developed by Jonas Salk does an excellent job of triggering an immune response that can prevent illness, but it doesn’t stop people from transmitting the virus to those around them. It wasn’t until the oral polio vaccine was developed that we had a vaccine that could do both.
The jury is still out on what effect COVID-19 vaccines have on transmission, and we will need much more comprehensive data before a verdict can be reached. It will require following large numbers of vaccinated people and their contacts over a lengthy period of time, but the challenging venture is a necessary one, critical to our ability to contain the pandemic.
In addition to requiring the data for themselves, the FDA can push for it to be made available publicly, beyond what is required by law. Trust in COVID vaccines is vital to controlling the pandemic. In some communities, years of medical mistreatment and systemic health challenges have made people wary of taking the vaccines, and conspiracy theories only add fuel to the fire. If the FDA approves these vaccines without the data available publicly, we only risk further undermining the public trust that is essential to our success. The drug makers are already preparing their applications for approval. Let’s hold them to account before it’s too late.