The U.S. Centers for Disease Control and Prevention has not been communicating well enough with educators, teachers unions say, as COVID-19 hospitalizations hit records in the country.

The safety of American public schools, which educate over 50 million kids, has become a hotly contested issue, pitting teachers' unions worried about the disease's spread in sometimes underfunded, antiquated buildings against local and state officials who want to keep schools open.

The CDC, the United States' national public health agency, is not offering teachers enough information or seeking their input, despite a long history of close contact, top union representatives say.

"CDC does not communicate the way it used to, frankly, in the Trump administration and the Biden administration, or in previous administrations," said Randi Weingarten, the president of the 1.7 million-member American Federation of Teachers (AFT).

The CDC didn't issue fresh guidance to schools about how to handle new five-day isolation rules for those infected, issued Dec. 27, until last week - well after schools reopened after the winter holiday break, Weingarten said.

Becky Pringle, president of the 3 million-member National Education Association, said her group was also seeking more communication with the CDC, but did not elaborate.

"I would hope that every person in this country would want CDC to be asking the largest union of educators— NEA — about how their guidance affects public education, so more, not less, communication is essential to getting this right for our students, schools and communities," she said in a statement to Reuters.