This is unacceptable, and it should alarm every American, regardless of political leanings.

C.D.C. is an agency under Health and Human Services. During our respective C.D.C. tenures, we did not always agree with our leaders, but they never gave us reason to doubt that they would rely on data-driven insights for our protection, or that they would support public health workers. We need only look to Operation Warp Speed during the first Trump administration — which produced highly effective and safe vaccines that saved millions of lives during the Covid-19 pandemic — as a shining example of what H.H.S. can accomplish when health and science are at the forefront of its mission.

The current H.H.S. leadership, however, operates under a very different set of rules. When Secretary Kennedy administered the oath of office to Dr. Monarez on July 31, he called her “a public health expert with unimpeachable scientific credentials.” But when she refused weeks later to rubber-stamp his dangerous and unfounded vaccine recommendations or heed his demand to fire senior C.D.C. staff members, he decided she was expendable.

These are not typical requests from a health secretary to a C.D.C. director. Not even close. None of us would have agreed to the secretary’s demands, and we applaud Dr. Monarez for standing up for the agency and the health of our communities.

When the C.D.C. was created in 1946, the average life expectancy in the United States was around 66 years. Today, it is more than 78 years. While medical advances have helped, it is public health that has played the biggest role in improving both the length and quality of life in our nation. The C.D.C. has led efforts to eradicate smallpox, increase access to lifesaving vaccinations and significantly reduce smoking rates. The agency is also on the front lines in communities across the country, delivering crucial but often less visible wins — such as containing an outbreak of H.I.V. cases in Scott County, Ind., or protecting residents in East Palestine, Ohio, from toxic chemical exposure.

The C.D.C. is not perfect. What institution is? But over its history, regardless of which party has controlled the White House or Congress, the agency has not wavered from its mission. To those on the C.D.C. staff who continue to perform their jobs heroically in the face of the excruciating circumstances, we offer our sincere thanks and appreciation. Their ongoing dedication is a model for all of us. But it’s clear that the agency is hurting badly. The loss of Dr. Monarez and other top leaders will make it far more difficult for C.D.C. to do what it has done for about 80 years, to work around the clock to protect Americans from threats to their lives and health.