As Omicron uncertainty mounts, return-to-office plans are being revised again.

The start of this year may seem uncomfortably similar to the beginning of 2021, with surging coronavirus case counts, event cancellations and companies revising their return-to-office plans. But in 2022, there are important differences in the path of the pandemic — and the policy response to it.

“We want to make sure there is a mechanism by which we can safely continue to keep society functioning while following the science,” Rochelle Walensky, the director of the Centers for Disease Control and Prevention, said recently.

The Omicron variant, while highly contagious, is seemingly less severe than previous strains of the coronavirus. As the government pushes to keep the U.S. economy open despite record cases — but rates of lower hospitalizations and deaths — it raises new questions for businesses preparing for a third year of the pandemic.

Government policies are shifting. Dr. Anthony Fauci said Sunday that it was “much more relevant” to focus on Covid hospitalizations instead of total cases, because many infections were asymptomatic, and he was more worried about potential strains on hospital systems.

The C.D.C. has halved its recommended isolation time for asymptomatic infections to five days from 10, a move that raised criticism (and inspired memes), but Dr. Fauci said the agency may revise its guidelines yet again.

And the Biden administration is signaling that it may change the definition of “fully vaccinated” to require booster shots, a prospect that could affect what 140 million Americans can and can’t do in public.

That leaves companies with a lot to consider. Some, like Goldman Sachs, are changing their vaccination policies. The Wall Street bank will require a booster shot for all employees and visitors entering its offices beginning Feb. 1.

Employers will also need to rethink their policies if they want to bring infected workers back to the office more quickly. This makes testing the next big issue, with the Biden administration scrambling to increase supply amid shortages.

Some big firms have been buying tests in bulk to give to employees, but smaller companies may not have similar capacity. Deciding whom to prioritize for tests, who pays for them, and how to verify the results will bedevil many boardrooms in the coming months.