"What is not legitimate is overcoming science," he said.
Often, Mr. McGowan and Mrs. Campbell mediated between Dr. Redfield and agency scientists as to when the White House requests and dictations came in: changes from former White House adviser Mr. Vought and Kellyanne Conway on choirs and fellowship, or suggestions from Ivanka Trump, the President's daughter and aide-de-camp , to schools.
"Every time science collided with messaging, messaging won," said McGowan.
Interfering episodes have sometimes become absurd, they said. In the spring the C.D.C. released an app that Americans could use to screen for symptoms of Covid-19. However, the Trump administration decided to develop a similar tool with Apple. White House officials then requested that the C.D.C. wipe his app off his website, said Mr. McGowan.
Ms. Campbell said that when the pandemic began, she was confident that the agency had the best scientists in the world at its disposal, "just as it has in the past."
“What was so different, however, was the political commitment, not just from H.H.S. But then, in the end, in many ways, the White House blocked what our scientists could do, ”she said.
Top C.D.C. Officials developed workarounds. Instead of releasing new guidelines for schools and electoral officials in the spring, they released “updates” to previous guidelines that skipped the formal Washington review. This prompted Washington officials to insist on checking the updates.
Brian Morgenstern, a White House spokesman, said, "All proposed policies and regulations that have the potential to have far-reaching implications for our economy, society and constitutional freedoms will be properly consulted by all stakeholders, including task force doctors, other experts and administrators."
A C.D.C. Speaker declined to comment.
Mr. McGowan and Mrs. Campbell both attended the University of Georgia and saw their C.D.C. Homecoming positions. Mr. McGowan said the two institutions he most revered in his childhood in Georgia were the C.D.C. and Coca-Cola.