Federal health officials have been instructed to temporarily stop any “external communications” to the public, according to two officials with knowledge of the situation.

The agencies are charged with making decisions that touch the lives of every American and are the source of crucial information to health-care providers.

The Centers for Disease Control and Prevention is going dark, along with other federal agencies within the umbrella of the U.S. Department of Health and Human Services. This week, the returning Trump administration told these agencies to stop talking to the public—for how long, no one knows.