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What full FDA approval for Covid-19 vaccines really means

The Pfizer/BioNTech shot got the green light from regulators — which could encourage some holdouts to get vaccinated.

Pedestrians, one pushing a stroller, walk past a sidewalk sign that reads, “Free Covid-19 vaccine here.”
A city-operated mobile pharmacy advertises the Covid-19 vaccine in Brooklyn on July 30.
Spencer Platt/Getty Images

Nearly nine months after the first Americans received their shots, the Covid-19 vaccine from Pfizer/BioNTech received full approval from the Food and Drug Administration for people 16 and older on Monday. This could help increase the number of people willing to get vaccines and make it easier to compel those who are less willing — if health officials can cut through the mounting confusion around their efficacy, booster shots, and the threat of the delta variant.

Covid-19 vaccines from Johnson & Johnson, Pfizer/BioNTech, and Moderna have thus far been distributed across the US under emergency use authorizations. This form of limited approval allows the FDA to fast-track the distribution of drugs, vaccines, and medical devices during a public health emergency, like a pandemic.

Getting an emergency use authorization requires data from clinical trials showing that an intervention is safe and effective, but the bar for full approval is higher. Now, with 200 million people at least partially vaccinated, the FDA has effectively removed the asterisks from Pfizer/BioNTech’s mRNA vaccine.

“While millions of people have already safely received Covid-19 vaccines, we recognize that for some, the FDA approval of a vaccine may now instill additional confidence to get vaccinated,” said Janet Woodcock, acting commissioner of the FDA, in a statement on Monday.

Full approval grants the vaccine manufacturers permission to advertise their products and allow them to continue selling them after the public health emergency around Covid-19 ends. For doctors, full approval also allows them to use vaccines off-label, potentially as booster shots.

But perhaps the most significant change would be a potential boost in public confidence in the vaccines, amid a rising tide of confounding information. Full approval could serve as a valuable messaging tool and help close some of the lingering gaps in immunization across the country.

A significant share of unvaccinated people — millions of people, according to polling — say that full approval will increase the likelihood that they’ll get a Covid-19 vaccine. These individuals may be hesitating “because they know there will be much more data available at the time of an approval ... three times as much data on safety and three times as much data on effectiveness,” said Sidney Wolfe, founder and senior adviser at the health research group at Public Citizen.

More employers may also be willing to require vaccines among their workers (some have already begun to do so). And full approval from the FDA could bolster support for these vaccines in other countries that look to the US agency for its rigor. However, to get the maximum public health value out of a full approval, messengers from the president on down to local doctors have to be ready to explain what it all means.

Full approval requires long-term evidence that Covid-19 vaccines are safe and effective

For vaccines, the FDA grants emergency use authorizations after it reviews at least two months of follow-up results for clinical trial participants who received the actual injection. For full approval, known in FDA-speak as a “biologics license application,” the agency wants to see six months of data to ensure there are no widespread problems or to detect adverse reactions. Both reviews examine safety and efficacy while also studying what the optimal distribution strategy might be.

In May, Pfizer and BioNTech submitted their license application. Moderna began its application in June, and Johnson & Johnson said it will begin the process later this year.

With vaccines in general, almost all complications that occur tend to happen shortly after the vaccine is administered, often within a day or two. Most side effects of the Covid-19 vaccines in the US tend to be mild or moderate, ranging from pain at the injection site to fatigue to fever. A very small number of recipients reported severe allergic reactions shortly after their shots, which is why most vaccine clinics have a waiting period where they can monitor patients for 15 to 30 minutes.

But in clinical trials, some extremely rare complications can be hard to detect even among tens of thousands of people after following them for two months. In April, the CDC and FDA paused the distribution of the Johnson & Johnson Covid-19 vaccine after 15 people reported a rare blood-clotting disorder out of the 8 million people who had received a dose at that point. After investigating, regulators concluded the benefits of the vaccine far outweigh the risks and allowed distribution to resume.

Monitoring clinical trial participants over six months also yields more information about how long protection from the vaccine lasts and whether any subsets of the population are more vulnerable. And it presents an opportunity to see how well the vaccines hold up against variants that were not widely circulating earlier in the pandemic.

This additional information — not just from clinical trials but from wide-scale distribution — helps the FDA identify any risks and better tailor its recommendations for use of the vaccine. Full approval also requires inspections of vaccine production facilities, looking at how the shots are made and how they’re packaged to ensure that production is consistent.

“That’s a much larger package of data, and that in itself means it takes much longer” to review, Wolfe said.

The licensing process for vaccines usually takes about a year. By granting full approval to the Pfizer/BioNTech vaccine just four months after the companies applied, Covid-19 vaccines have broken yet another speed record.

One caveat is that the full vaccine license only applies to the specific age groups included in a given clinical trial. The original trials mainly included adults, and Covid-19 vaccine testing in younger children has only recently begun, so the FDA has fully approved the Pfizer/BioNTech vaccine for use in adults 16 and older. Children 12 to 15 can continue to receive the shot under the emergency use authorization that was already in place.

Full FDA approval for a Covid-19 vaccine may help convince the hesitant

At this point, the majority of adults in the US have received at least one dose of a Covid-19 vaccine under an emergency use authorization. The spread of the delta variant has increased the rate of new vaccinations, which reached more than a million doses in a day on August 19, but the rate is still far below the April peak of more than 4.4 million doses per day. There remain pockets of the country where fewer than half of all eligible people have been vaccinated, and these regions are driving the rise in new Covid-19 cases, hospitalizations, and deaths.

There are several factors that divide the vaccinated from the unvaccinated, including political affiliation, race, income, and age. The reasons these people cite vary, such as a lack of access, a belief that Covid-19 isn’t that serious, and concerns that the vaccines have not been fully vetted.

According to polling from the Kaiser Family Foundation, almost one-third of unvaccinated people said they would be more inclined to get a shot if it graduates from an emergency use authorization to a full license. Full FDA approval could mean a lot for this last group of people.

But convincing people to get shots is not the job of the FDA; that falls to other public health messengers, and they have to be prepared to seize the opportunity. “It can have a modest effect or be a game changer, depending on how it’s handled,” said Drew Altman, president and CEO of the Kaiser Family Foundation. “It’s a question then of what the president does, what state and local public health leaders do, what the experts on television do.”

It’s not clear that people who cite the lack of FDA approval as a reason for not getting vaccinated are genuinely concerned with regulatory procedure or whether that’s just a proxy for general hesitancy. There’s also widespread confusion about the approval process: Kaiser’s polling also showed that at least two-thirds of US adults believed that Covid-19 vaccines already had full approval or weren’t sure about their regulatory status.

As for vaccine mandates, it’s already legal for private and public institutions to require their employees and customers to get shots. Companies like Google, Disney, and Walmart have begun to require many workers to get Covid-19 vaccines. But full approval could tip more employers, airlines, event venues, and other institutions that are on the fence to impose vaccinate mandates.

“I would look for significant movement on the part of more employers after full approval comes down from the FDA,” Altman said.

Now that the Pfizer/BioNTech vaccine is fully approved for people 16 and older, that doesn’t mean Moderna and Johnson & Johnson will stop distributing their vaccines under emergency use authorizations. While one of the conditions for granting an emergency use authorization is that there is no FDA-approved alternative available, emergencies like Covid-19 affect the calculus, the agency told Vox.

“For example, if the approved vaccine is only available in limited quantities, that vaccine may not be considered adequate to address the public health emergency,” said an FDA spokesperson in an email. “Another example would be if the vaccine is approved for use only in a limited population, then that vaccine may not be considered adequate to address the public health emergency for other populations.”

All the while, the dynamics of the pandemic are still changing, particularly with the surging delta variant of the coronavirus. While vaccines remain highly protective against severe Covid-19, delta seems to have increased the likelihood of breakthrough infections. Recent CDC data suggests that the shots aren’t as protective for vulnerable people like older adults who were vaccinated many months ago.

To counter this, the FDA is now on the verge of approving booster doses for many Covid-19 vaccine recipients. Meanwhile, the Centers for Disease Control and Prevention has gone back to recommending face masks in some circumstances for vaccinated people.

For health officials, it’s a fine line to walk: reassuring people vaccines are safe and effective while also noting that precautions are still needed. Regulators like the FDA also have to balance the needs of an urgent public health crisis with taking the time to go through the proper procedures.

And there are tough challenges that will remain even after a vaccine gets the bright green light from the FDA. There are still parts of the US where vaccination rates remain stubbornly low, and many unvaccinated people are not just hesitant but outright refusing to get immunized. Convincing these holdouts is difficult, but necessary, because as long as they remain unprotected, the virus will have ample opportunity to wreak havoc.

Update, August 23, 10 am ET: This article has been updated with the FDA’s full approval of the Pfizer/BioNTech vaccine.