WASHINGTON—As Covid-19 cases climb across the U.S., President Biden and his administration are preparing Americans to accept the virus as a part of daily life, in a break from a year ago when he took office with a pledge to rein in the pandemic and months later said the nation was “closer than ever to declaring our independence from a deadly virus.”

The recalibration of Mr. Biden’s message comes as the country braces for another round of disruptions wrought by the pandemic. A growing number of schools temporarily have returned to virtual instruction and many businesses are strained by staffing shortages, in both cases due to infections triggered by the highly transmissible Omicron variant. Nearly 1,700 U.S. flights were canceled Wednesday, the 11th straight day of more than 1,000 cancellations, and many states warned that ongoing testing shortages will make it harder to return people to work and school.