Yet amid this latest wave of COVID-19 cases, 74% of companies that still have employees working remotely are planning on returning to the office this fall, according to a survey conducted in June by staffing firm LaSalle Network. 

Even in hard-hit cities like New York, an estimated 62% of workers are expected to be back at work in September, according to the latest survey from the Partnership for New York City. About 12% of Manhattan office workers had started working out of their offices again as of late May. 

But with cases on the rise, companies are bracing for changes and, in some cases, rethinking their timeline entirely. In fact, Apple announced last week that it would push back plans to bring the majority of its over 100,000 workers back by a month. Instead of returning in September, the technology company is now aiming for early October. 

While it’s too soon to tell if other major companies will follow Apple’s lead, experts say that most are being cautious as they move forward with their plans. The risk that companies would reverse course entirely, close offices, and send the majority of their workforces back home is “quite low,” even with the recent Delta variant surges, says Mary Kay O’Neill, a partner and senior clinical advisor at human resources consulting firm Mercer that works with companies globally on their health benefits, talent recruitment, risk management strategies and re-opening plans.

In many states and regions in the U.S., a significant level of the population is already vaccinated, meaning that it’s not as likely that hospitals and health centers will be overflowing with COVID cases, O’Neill points out. That was one of the big reasons why employers sent workers home last spring and municipalities issued stay-at-home orders. “That’s not happening right now,” she says, so it’s less likely employers will continue to keep workers at home.  

In fact, Facebook, one the earliest companies to send its workers home last year, tells Fortune that it’s still planning to bring employees back in the fall. “We’re on track to open most of our U.S. offices at 50% capacity by early September, and likely reopening fully in October as long as the health data supports doing so,” spokesman Tracy Clayton says. 

But Clayton stresses that Facebook is taking a “measured approach” to returning to the office and monitoring key health metrics such as local case and vaccination rates, ICU capacity, local access to testing and therapeutics, as well as government guidance. “Data, not dates, is what drives our return to office thinking.”

Some financial companies such as Citigroup and Bank of America are also still aiming for a return to the office in September, but are monitoring the situation with the Delta variant. Others, such as Goldman Sachs and JPMorgan Chase, have already required employees to return to the office. 

It’s actually the companies that are rushing to return to normal that worry Di Ann Sanchez, a Texas-based HR consultant who works with about 100 businesses in industries ranging from healthcare and construction to banking and hospitality. 

“I’ve got companies that just think they can go back to how it was,” Sanchez says. Instead, she’s encouraging her clients to be creative and cautious. “We need to look at a new definition of work,” she says. Most of her days now are spent helping managers and executives understand that they can’t go back to expecting life as it was pre-pandemic with employees in the office five days a week and no safety protocols.  

Employers will likely need to be more willing to provide more flexibility not for health reasons, but also for employee retention. Roughly half of workers who are still working remotely say they would consider quitting if their employer required them back at the office full-time, according to a survey of over 2,000 workers Fortune fielded in June.

Yet some time in the office is likely for most workers, and in many cases, it will likely include companies being more forceful about COVID vaccines. That’s because the U.S. Equal Employment Opportunity Commission has issued guidance that companies can ask employees about their vaccine status and require they get vaccinated without violating HIPPA and other federal laws. 

Many employers initially worried about the legal liabilities of requiring employees to get vaccinated, but these concerns have ebbed with the latest update from the EEOC. “We’ll see more companies saying, ‘I’m going to require a vaccine before you can come into the workplace,’” says Julie Stone, a national health care practice leader at Willis Towers Watson. 

About a third of Fortune 500 CEOs say they’re considering requiring their employees to have vaccines, according to Fortune data. So far, however, only about 10% are actually planning to put vaccine mandates in place.

Many workers can expect companies to require everyone wear masks, even those who are vaccinated. That’s especially true if there’s currently a high number of COVID cases in their region, O’Neill says. Sanchez is also recommending masks for all employees. “I’m telling my clients, whether they have their shots or not, to continue wearing masks because of the Delta variant,” Sanchez adds, saying that many of her clients are based in areas that are already seeing a surge. 

Both companies and workers will need to be flexible and informed over the next few months. Employers should know and understand what’s changed in my location or locations in regards to both the health data, as well as the local and state safety guidelines. 

“People will be going back to work and seeing what happens,” O’Neill says. “This is the next experiment.”