Some business leaders are in favor of requiring their employees take COVID-19 vaccines.

Seventy-two percent of current and recent CEOs of major companies signaled an openness to vaccine mandates, according to a poll held Tuesday at a virtual summit by the Yale Chief Executive Leadership Institute.

The broad question did not specify whether the mandate would apply to all employees or just ones who needed to work in close proximity to customers and colleagues.

Several CEOs indicated that such a mandate has not yet been formulated at their companies and they want to see how early rounds of vaccinations go. Companies may also be reluctant to require that employees take vaccines until they have been fully approved by the FDA. Last week, the agency issued an emergency use authorization for Pfizer’s vaccine.

The debate come as health authorities seek to reassure the public about the safety of vaccines and as Corporate America takes a more vocal stance on crucial issues including climate change.

“There was a surprising amount of openness to the idea of mandates for vaccines,” said Jeffrey Sonnenfeld, founder of the Yale Chief Executive Leadership Institute.

‘Too soon to say’

The Yale summit included business leaders from major US-based companies, including Walmart, Goldman Sachs and eBay.

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“It’s too early to say,” American Airlines CEO Doug Parker said during the virtual summit. “Let the vaccines be distributed, see what the acceptance rates are…In the end, we’ll all have to make the best decision for our individual companies.”

Parker added that some nations may require vaccines before airlines can even enter the country.

MetLife CEO Michel Khalaf said his focus now is on ensuring employees have access to vaccines.

“Down the road, we can make a decision on whether to mandate or not,” Khalaf said during the Yale event. “For now, it’s too soon to say we should mandate a vaccine.”

Others think that vaccine mandates go a step too far.

“Business has a huge role to play in helping set the tone on the importance of vaccines,” Mark Weinberger, the former CEO of EY and a director at MetLife and Johnson & Johnson, told CNN Business. “But to say you’re going to be fired if you’re scared to death to take a vaccine, that’s a difficult position for CEOs to take.”

Are vaccine mandates legal?

Legal experts say companies can require their employees to get vaccinated. Some jobs already have such requirements. For example, hospitals may require workers to get flu or hepatitis B vaccines.

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“Employers have the right to set workplace health and safety conditions,” said Dorit Reiss, a law professor at the University of California, Hastings.

However, there are limits to such mandates. For instance, Reiss said that companies may need to grant exemptions or accommodations to employees on medical or religious grounds.

Another question is whether vaccines can be required if they haven’t been fully blessed by regulators yet.

“There is some legal uncertainty whether you can mandate a vaccine under emergency use authorization,” said Reiss. “I suspect some employers will go ahead and mandate. It will be challenged and the courts could go either way.”

Who would the mandate apply to?

Sonnenfeld said vaccine mandates can help companies promote a culture of safety.

“If a safe work environment is part of their culture and brand, more power to them,” he said.

David Gibbs, the CEO of Pizza Hut and Taco Bell owner Yum Brands, said at the Yale summit that his company is focused for now on enforcing its policies around mask wearing and handwashing.

“I don’t think we’ve made a decision on that,” Gibbs said of a vaccine mandate. “It’s something we’ll look at.”

Howard Forman, founder of Yale’s MD/MBA program, said that it’s possible the next few months will reveal there are certain populations that vaccines may not be suitable for.

“You might have to make exclusions for those groups,” he said.

Still, Forman said it makes sense for some companies to mandate vaccines after the FDA fully approves them.

“If you want your people in the office, on factory floors or facing customers, you should want them to be as safe as possible,” Forman said during an interview. “Not every employee, but ones that fit categories where you can’t be working from home all the time.”