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

President Trump has imposed temporary freezes at the National Institutes of Health on meetings, travel, communications and hiring, citing the need to review protocols.

In a memo obtained by NPR, acting Health Secretary Dorothy Fink forbade staff from public communications on most matters until Feb. 1, unless they get express approval from "a presidential appointee."