More than half the adults in the U.S. have now gotten at least one shot of a COVID-19 vaccine. And as more people get vaccinated, a lot of companies are thinking more about whether vaccinations are key to bringing employees who’ve been working from home back into the office.

According to a new study from Arizona State University and the Rockefeller Foundation, about 90% of U.S. companies now say they will either require or encourage employees to get vaccinated. And 65% of them say they’ll offer incentives to their employees to do so.

The supermarket chain Lidl isn’t requiring U.S. employees to get the vaccine., but it is giving them a $200 bonus if they do. “Once you get your second vaccine, you call our health and safety hotline, the $200 benefit would be usually right on your next paycheck,” said Will Harwood, head of communications at Lidl U.S. About 15% of employees have claimed their $200, Harwood said, and that number is growing.

At this point, more companies seem inclined to offer incentives for vaccination instead of requiring it. Kosali Simon at Indiana University said that’s a good place to start. 

“Any time an employer mandates something, we know that there is going to be goodwill cost. I think we’re waiting to see how well the softer approaches of ‘provide information, incentivize softly with decision tools’ go before we see some more mandate-type actions,” she said.

But if not enough people choose to get vaccinated, that could change said Mara Aspinall, who worked on the study at Arizona State. “I believe that this is a moving target, one that will see more employers requiring or encouraging vaccination,” she said.

Maybe even by making the vaccine available at the office, Aspinall said, like the flu shot is. “87% of employers said they would allow vaccinations at their facility,” she said. That, Aspinall added, could go a long way toward making it both accessible and comfortable for more people to get vaccinated.