The U.S. Food and Drug Administration’s full approval of Pfizer’s COVID-19 vaccine Monday may inspire some unvaccinated Illinois residents to roll up their sleeves, but the bigger impact will likely be in prompting large organizations to mandate the shots, health and legal experts say.

“I think it’s more significant than people realize because I believe corporations and schools are really going to move the needle for increasing vaccinations,” Dr. Mathew Philip, a primary care physician and senior vice president of clinical innovation at DuPage Medical Group, said of the vaccine gaining FDA approval. “This gives those organizations cover to do that. This is going to get us a lot closer to that herd immunity.”

Until Monday, all three COVID-19 vaccines used in the U.S. had been allowed under emergency use authorizations, not full FDA approval. The Pfizer approval comes as COVID-19 cases and hospitalizations continue to rise in Illinois, fueled by the highly contagious delta variant.

Some Illinois vaccine holdouts are already seeking shots. As of Monday, about 59% of Illinois residents ages 12 and older were fully vaccinated, and nearly 76% had received at least one dose.

Two patients contacted Dr. Laura Zimmermann, a primary care doctor at Rush University Medical Center, shortly after the FDA approval Monday morning to let her know they were ready for their shots.

A handful of patients have also told Philip, with DuPage Medical Group, that they’ve been waiting for FDA approval before getting vaccinated.

“Despite over 200 million doses of Pfizer being given, people still feel like this is an experiment because it has emergency use authorization attached to its name,” Philip said.

Patients have also told Dr. Lee Francis, an internal medicine physician and the CEO of Erie Family Health Centers, that they wanted to see the FDA grant the vaccines full approval before taking their turns.

About 31% of unvaccinated U.S. adults surveyed in June by the Kaiser Family Foundation said they would be more likely to get vaccinated if one of the vaccines gained full FDA approval.

Still, local experts say the FDA’s approval is likely to be most influential when it comes to organizations mandating the shots, rather than changing the minds of large numbers of unvaccinated individuals.

“I think it will help a few people, move them toward wanting the vaccine, but I think the biggest benefit will probably come from the comfort bigger organizations have in mandates,” said Dr. Jeffrey Linder, a primary care doctor at Northwestern Medicine and chief of the division of general internal medicine and geriatrics at Northwestern University Feinberg School of Medicine.

Already, a number of organizations have reacted. Shortly after the FDA announced its approval Monday, Mayor Lori Lightfoot said she would require the vaccine for city workers, and the Pentagon said it would require shots for members of the U.S. military. President Joe Biden urged U.S. employers to require their workers to get shots, in a speech shortly after FDA approval was announced Monday.

Many — but not all — Chicago-area hospitals have announced vaccine mandates for workers in recent weeks, as have several large, Chicago-based employers, including United Airlines. Cook County and Chicago Public Schools are also requiring shots for workers.

Employers were already allowed to mandate the vaccines, even before they gained full FDA approval, though they must consider exemptions for medical or religious reasons. The FDA’s approval, however, might make some organizations feel more at ease requiring their employees to get shots, said Margo Wolf O’Donnell, co-chair of the labor and employment law group at law firm Benesch in Chicago.

“Many employers have been waiting for this moment, for the vaccine to receive full approval,” O’Donnell said. “If you want a mandate, it’s easier, it seems, for your workforce to accept it if your vaccine is fully approved.”

Those vaccine mandates may be especially powerful in boosting Illinois’ vaccination rate, as many individuals continue to decline vaccines, even with full FDA approval.

Zimmermann, with Rush University Medical Center, doesn’t think the FDA’s approval will alter the opinions of all unvaccinated individuals.

“While I think this is going to help, the FDA’s Pfizer approval is not going to be a panacea,” Zimmermann said. “I don’t foresee it opening the floodgates.”

Larry Work, 65, of Wheaton, decided not to get vaccinated, and his mind was not changed by the FDA’s approval.

Work said he is concerned about possible side effects and believes the FDA’s approval was politically motivated. He also said he has recovered from COVID-19 and believes he has immunity, though his doctor has told him to get the vaccine.

“I have a lot of questions. I have a lot of questions about the approval, even,” he said.

Patients have a number of reasons for not getting vaccinated that have little to do with FDA approval, Zimmermann said.

Some of her patients are wary of any type of medical intervention because of past negative experiences with health care systems, she said. Others are relying on misinformation. Some worry that if they’re allergic to other medications they’ll be allergic to the vaccines, which Zimmermann said is not the case.

Many others want to wait and see how the vaccines affect those who’ve already taken them. Zimmermanntells patients that plenty of people have already been vaccinated without major problems.

“You can say now over 200 million people have gotten the first dose of the vaccine, and if the vaccine were really harmful, those would be the folks flooding our hospitals,” Zimmermann said. “Instead, what we’re seeing is the folks flooding hospitals in places like Florida are those who are unvaccinated.”

The state reported 4,203 new confirmed and probable coronavirus cases Saturday, 2,007 on Sunday and 3,003 on Monday. That’s up from the first half of July, when the state was reporting fewer than 1,000 new cases each day.

In Illinois, 2,064 people were hospitalized with COVID-19 as of Sunday, more than double the number in hospitals on Aug. 1.