At a time when the nation is desperate for authoritative information about the coronavirus pandemic, the country's foremost agency for fighting infectious disease outbreaks has gone conspicuously silent.

"I want to assure Americans that we have a team of public health experts," President Trump said at Tuesday evening's coronavirus task force briefing — a bit of reassurance that probably would not have been necessary if that briefing had included anyone from the Centers for Disease Control and Prevention.

The CDC normally takes the lead in outbreaks, ranging from the 2009 flu pandemic to Ebola to the lung injuries caused by vaping. Its recent absence from the national stage has led to fears that the agency's objective, science-based approach is being ignored, especially as Trump signals that he hopes to relax restrictions on social gatherings by Easter to help revive the economy.

That idea has horrified public health experts outside of the government, who say that the virus is spreading rapidly and that social distancing measures still need time to work.

"This has never happened before. In the nearly 75 years that the CDC has existed, in every single infectious disease outbreak the country has dealt with, the CDC has been central. It's been at the decision table, and it's been at the podium," says former CDC director Tom Frieden, who is now president and CEO of the global health initiative Resolve to Save Lives.

"I feel less safe because it's not clear that the CDC's expertise is feeding into the decisions that are being made, and these are life and death decisions," says Frieden. "We are less safe because the CDC doesn't have the voice and the role it needs to have."

The CDC is normally a credible, reliable source of infectious disease knowledge, led by physicians, scientists and epidemiologists capable of fielding detailed questions about what is scientifically known and what is not.

In past health emergencies, the agency has not only provided specific numbers and data about the changing status of an epidemic, but also offered informed commentary on the likely course of an outbreak and the best known strategies for mitigation and containment. The agency is usually in close contact with state public health agencies, and has an overview on what is happening across the entire country.

Though represented behind the scenes on the White House's coronavirus task force, the CDC hasn't held its own press briefing for reporters in two weeks. Those briefings had been happening frequently as the novel coronavirus outbreak began, but stopped abruptly early this month. The last one was held on March 9. An inquiry from NPR to the CDC about why the agency's briefings stopped and whether they would resume went unanswered.

Meanwhile, various members of the White House task force have taken over the job of informing the public. Much time is spent in briefings on economic or political considerations like legislation or the performance of the stock market, with questions often being answered by the president or Vice President Mike Pence.

Asked, for example, why Easter was targeted as a possible timeline for lifting social distancing measures, the president replied, "I just thought it was a beautiful time. It would be a beautiful time, a beautiful timeline. It's a great day."

A follow-up question asked whether the time was based on any data, and the president again said that he thought it would be a beautiful timeline.

"I am concerned that I haven't seen CDC as a participant in the briefings in days, and that CDC does not seem to be speaking otherwise directly to the public, which is really a break with how they have communicated about past epidemics in the United States," says Tom Inglesby, director of the Johns Hopkins Center for Health Security.

"We're in the middle of the most serious epidemic that this country has experienced probably in 100 years, and CDC is the organization that studies and prepares for and responds to epidemics, and is known throughout the world for that expertise," says Inglesby. "To me, it seems like they should be a central participant in all communications with the public."

At the White House briefings, science and public health questions often get addressed by Anthony Fauci, the head of the National Institute of Allergy and Infectious Diseases, or the coronavirus response coordinator, Ambassador Deborah Birx.

Patrick Semansky/AP

Dr. Anthony Fauci (left), director of the National Institute of Allergy and Infectious Diseases, confers with Dr. Robert Redfield, director of the Centers for Disease Control and Prevention, at a congressional hearing on March 11.

The two, both doctors, seem to walk a tightrope of trying not to annoy the president while deftly attempting to temper some of his more optimistic assertions, like the potential of the drug chloroquine to treat COVID-19.

Fauci's absence on Monday led to speculation that his willingness to contradict the president had led to his banishment. But on Tuesday, Fauci spoke during the White House briefing, and received praise from Trump.

Inglesby says of the doctor: "Dr. Fauci is a national treasure and is extraordinary. But he has many, many things to explain and be responsible for, including the entire development process for vaccines and medicines and the research agenda."

It is CDC officials who actually have the mission of preparing the nation to control epidemics, he says, "so they should be there with Dr. Fauci."

"Dr. Fauci is one of the world's greatest researchers. He has a fantastic career; he is a wonderful human being. He is able to navigate very complex scientific and political issues extremely well," agrees Frieden. "But CDC is the country's public health agency. Fighting this pandemic without CDC central to that fight is like fighting it with one hand tied behind your back."

Top officials who could be communicating with the public more regularly include CDC Director Robert Redfield; CDC principal deputy director, Anne Schuchat; and Nancy Messonnier, who is director of the CDC's National Center for Immunization and Respiratory Diseases.

"Those are the most important people to have out there because of the positions they hold, what they represent, the fact that many of them are physicians, and all of them have expertise in public health and particularly in infectious disease," says Bill Pierce of APCO Worldwide, who served as spokesperson for the Department of Health and Human Services under President George W. Bush.

"I think we need to hear from them more consistently," says Pierce. "Clearly, we have heard a lot from Tony Fauci. But I think we need to hear from more of them. And I think there needs to be more than just the briefing at the White House. That's important, but also I think the agencies themselves can do briefings."

Messonnier is scheduled to speak at a teleconference on Thursday — but it's one organized by the State Department, aimed largely at foreign media, to discuss how the CDC is coordinating with other countries.

Some question whether Redfield is up to the task of serving as a strong public communicator, noting that his recent testimony before lawmakers about the coronavirus outbreak did not inspire confidence.

"He did a terrible job in front of Congress. If that's any indication of the way he would communicate, we probably don't want to see him," says Paul Argenti, professor of corporate communication at the Tuck School of Business at Dartmouth.

In a crisis, says Argenti, there ideally needs to be one voice delivering one consistent message, much as Gov. Andrew Cuomo has been doing in New York.

And if multiple officials are addressing the public, they shouldn't be sending mixed messages, Argenti adds.

"They don't have to be maniacally consistent, but they have to actually make sense when put together. They cannot be contradictory," he says. "And what we are seeing right now are contradictory messages."

In difficult times, Argenti says, people are desperate for the voice of a leader.

"And so I do think it is a good idea for President Trump to continue to try to get this right," he says. "But boy, it would be good if he conferred with his health experts to make sure that that message is both correct and consistent."

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