As more coronavirus vaccines are approved and made available, employers are increasingly signaling they could require workers to get immunized before returning to the office, a new survey shows.

Nine in 10 senior-level executives queried by workplace health care concierge service Eden Health said they would require vaccinations from their workforce within federal guidelines, in a survey of 400 executives across a wide range of industries conducted in December. A large majority of the executives said they would look to provide their staff with vaccines if possible and incentivize inoculation.

Eden Health surveyed leaders from construction, manufacturing, warehouse, scientific and other office-using firms with between 51 and 5,000 employees. Seventy percent said they plan to offer the COVID-19 vaccine on-site to their workforce once it’s widely available. They also plan to offer incentives, such as lower personal protective equipment requirements, offering wellness programs and giving out cash or gifts.

The survey indicated respondents would follow federal guidelines, but the federal Food and Drug Administration's emergency use authorization for the vaccines bars mandatory inoculations, the Centers for Disease Control and Prevention confirmed last year. The vaccines won't be licensed by the FDA until vetted by clinical trials that will last approximately two years. Additional limited exceptions to potential employers' vaccination requirements can include religious or disability reasons, the U.S. Equal Employment Opportunity Commission said in December.

 Respondents were optimistic on a return to work, with 87% anticipating a return to workplaces at levels similar to the pre-pandemic era by the end of 2021. Just 14% of employers told Eden Health they believe telecommuting will be far more prevalent. The remote work answer aligns with a January PwC survey, in which 13% of executive respondents said they'd want to let go of the office for good.

Landlords have chased new technologies and flexible workspace models to promote confidence among returning workers after a year of record struggles in some of the nation's largest office markets. Daily office occupancies, estimated as low as 5% during the winter season, were just 15% last month, according to Kastle Systems, a national supplier of commercial property security systems that tracked access card swipes.

The Eden Health survey was released as Johnson & Johnson begins shipping 4 million doses of its single-shot COVID-19 vaccine, and as the CDC Monday announced 50 million people had received at least one dose of the Pfizer or Moderna vaccines.

Eden Health CEO Matt McCambridge shared the survey results on Bisnow's Boston’s Path to Healthy Buildings event last week.

“As we think about what landlords can participate with, making it really simple and easy to get access to the vaccine, especially in the long term of getting the entire employee base vaccinated, is going to be critically important,” McCambridge said.

Eden Health has set up medical facilities with landlords at sites in major markets across the nation, including at offices in Chicago, New Jersey, Boston, Washington, D.C., Houston and Los Angeles, McCambridge said. The company offered flu shots at sites last year, a spokeswoman said.

Eden's survey shows vastly more enthusiasm for a vaccine requirement than previously released studies: a January questionnaire of 150 C-suite executives by West Monroe found a nearly 50-50 split on vaccine requirements, with smaller companies reportedly less likely to require the shot. Willis Towers Watson found just 45% of employers are considering proof of vaccination for in-person work, while 34% may require vaccination as a condition of employment. Workplace leaders may also need to bargain with labor unions, according to HR Dive.