Pfizer’s Covid-19 vaccine is currently only authorized for emergency use in the United States, but its full approval by the US Food and Drug Administration could happen within weeks.

The ramifications could alter the course of the pandemic in several ways.

First, full approval of a Covid-19 vaccine could persuade more people to get vaccinated.

More than 30% of the eligible population in the United States still hasn’t gotten a vaccine.

To qualify for emergency use authorization, Covid-19 vaccine makers submitted about three months of clinical trial data. This included at least 2 months of safety data on fully vaccinated participants, since most vaccine side effects occur 2-3 months after the vaccination.

For some Americans, that hasn’t been enough data to convince them to get the shot.

Full approval of a Covid-19 vaccine requires much more data, including safety and efficacy data generated in the real-world, outside of a clinical trial. The CDC has been tracking real-world data on the vaccines and more than 165 million people in the US are now vaccinated against the virus.

The extra data may help convince more people that the vaccines are not dangerous.

“For some, getting a full FDA approval will help allay that fear. Even if it’s just a relatively small number of people. Every little bit helps against this virus,” Dr. David Dowdy, an associate professor in the division of infectious disease epidemiology at Johns Hopkins Bloomberg School of Public Health, said.

Three in ten unvaccinated adults said they would be more likely to get vaccinated if one of the vaccines moves to full approval, according to a survey from the Kaiser Family Foundation.

However, Kaiser cautioned that some people it surveyed were confused about the shots. Two-thirds thought the vaccines already had full approval or they were unsure about it. This finding may just mean that full approval “is a proxy for general safety concerns.”

Dr. Michael Wolf, the Associate Vice Chair for Research, Department of Medicine at Northwestern Feinberg School of Medicine expects approval would get about 5-10% more individuals worried about safety to get vaccinated.

The FDA is currently “working around the clock” on approval of the Covid-19 vaccine, according to Dr. Paul Offit, a prominent member of the FDA’s vaccine advisory committee and director of the Vaccine Education Center at the Children’s Hospital of Philadelphia.

“I think from the standpoint of the public, it really shouldn’t matter,” Offit said. “It’s been given to half of the American population. We have more than 300 million doses out there. This is far from experimental. We have a tremendous safety and efficacy portfolio on these vaccines — I mean, it’s more than most licensed products that are out there now.”

And yet he recognized that, at least for some, it does matter. He said the FDA knows that, too.

“I think they realize that at least there’s a psychological issue with how these vaccines are viewed, in terms of whether they’re a licensed product or just approved through EUA,” Offit said.

‘Carrots’ and ‘sticks’ will encourage vaccination

Full approval of a Covid-19 vaccine could also make workplace mandates easier. Many unvaccinated people would face a financial reason to get one; they’ll need it to keep their jobs.

“FDA approval alone is not going to make many individuals run out and get it now, but you’re going to start seeing health systems and employers feel more emboldened to require them,” Wolf said. “There’s precedent for mandatory vaccinations and immunizations.”

Workplaces already have the legal authority to mandate the Covid-19 vaccine, according to the US Equal Employment Opportunity Commission. But full approval could give any legal challenge less potency.

“FDA approval is the gold standard. The world’s regulators look to our FDA as the beacon when it comes to such issues as this,” George Karavetsos, a legal expert who had worked at the FDA and now provides strategic advice to FDA regulated companies as an attorney at Buchanan Ingersoll Rooney, said. “I can assure you, they’re going to make sure they got this right.”

Erik Nisbet, the Owen L. Coon Endowed Professor of Policy Analysis & Communication and director of the Center for Communication & Public Policy in the School of Communication at Northwestern University, agreed.

“If you ever want to get beyond 70% threshold of people who have gotten a vaccination so far, you need to have carrots and you have to have sticks,” Nisbet said. “The only way to do that is the mandate. Authorization takes out one of the impediments to more widespread mandates.”

A little political cover

Full approval may also provide political cover to get more people vaccinated. On Wednesday, Louisiana’s Governor John Bel Edwards said he would not consider requiring the vaccine for state employees “unless and until the FDA grants full licensure to one of more of the Covid vaccines.” The state has the highest per capita number of cases of any state and one of the lowest vaccination rates.

San Francisco announced that it would require all city employees to be vaccinated no later than 10 weeks after FDA full approval.

Full approval may even be able to override laws like the one in Ohio that bans vaccine mandates under emergency use authorization, according to Nisbet.

“Approval kicks that out of the way,” he said.

A potential booster bonus?

Full approval may also mean that the fully vaccinated could get an additional vaccine, even before boosters are approved.

“Approval will make it easier for physicians to give the vaccine off label,” Dowdy explained. “If people can convince their doctor they need one.”

Many scientists hope people won’t do that. While a number of clinical trials are underway, boosters are not yet recommended by the FDA and the CDC.

Trials have shown immunocompromised people may not respond as well to the vaccines and may need a booster. There is an effort to make boosters for that population available “very soon,” Dr. Anthony Fauci, head of the National Institutes for Allergies and Infectious Diseases, said on Tuesday.

“Right now, what we really want to do is get the patient population here in the US to at least get one shot and not get ahead of the data,” said Melissa Tice, program director of regulatory affairs and assistant professor of clinical research and leadership at George Washington University School of Medicine & Health Sciences. “Hopefully, approval will at least get more people to get their first dose.”

What does approval mean for kids?

It remains unclear how having a fully licensed coronavirus vaccine may impact the timeline of authorizing or approving the coronavirus vaccines for children younger than 12 — if at all, Offit said.

The Pfizer/BioNTech Covid-29 vaccine is currently authorized for ages 12 and older, whereas the Moderna and Johnson & Johnson vaccines are authorized only for adults 18 and older.

“Does getting full approval for an adult vaccine, does that matter in terms of speeding up the process for approval for the childhood vaccines? I think the answer to that question is probably no,” Offit told CNN on Friday.

Overall, “this is all sort of new territory — the notion of emergency use authorization obviously is new, certainly for vaccines that have been used to this extent. We had EUAs for anthrax vaccines, but that’s not this,” he said. “I’m not sure how the FDA views this.”