WASHINGTON — Throughout the fall, the Biden administration touted its ability to open schools for in-person instruction in the midst of a pandemic. “Now over 99 percent of our schools are open,” President Biden said last month, drawing a contrast with his predecessor, Donald Trump.

But the Omicron wave of the coronavirus has challenged that promise, leading schools to close across the country. According to data site Burbio, more than 2,700 schools began 2022 either with remote instruction or with a day off.

Parents took to social media on Monday to lament the return of “Zoom school,” which in some cases was announced with little notice, while some educators said remote