U.S. health agencies including the CDC this week canceled meetings with external groups, paused some public health publications and told employees to freeze travel after directives from the Department of Health and Human Services,

The halt has frozen research grants, meetings and key health updates. “Everything is basically in chaos,” said one cancer researcher.

The U.S. Department of Health and Human Services has paused public communications until Feb. 1 as Trump appointees take control of health agencies.

The Trump administration’s freeze on some government work and communications on health topics pending a political review is alarming the nation’s scientists, who say the move could delay essential information and slow funding for potentially life-saving initiatives.

Scientific meetings were canceled, and research data on the bird flu outbreak was delayed, amid confusion over the directive.