When widespread public health emergencies like swine flu surface, it falls largely on three key people to take charge of the government's response: the secretary of Health and Human Services, the director of the Centers for Disease Control and Prevention and the commissioner of the Food and Drug Administration.
But nearly 100 days into the Obama administration, all three of those critical posts are vacant.
Visit ABC News' special section on swine flu to separate the facts from the myths, learn how to prevent the virus, and link to information from the Centers for Disease Control and Prevention and the World Health Organization.
Though Kansas Gov. Kathleen Sebelius is expected to be confirmed as secretary of Health and Human Services Tuesday, today HHS is the only department within the executive branch of government lacking a secretary.
And while some said holes at the highest levels of government are impeding the response to swine flu, others insisted the vacancies are not a problem.
"Philharmonics play without a conductor," a top federal health official told ABC News today. "There are a lot of people 'round who have been breathing this stuff for a long time."
Of 20 top spots at HHS, 19 are being filled by acting career and political employees, and the 20th position is empty.
"Our response is in no way hindered or hampered by not having a permanent secretary at HHS right now," White House press secretary Robert Gibbs said this afternoon.
Others, however, disagreed. This afternoon, former HHS Secretary Michael Leavitt called having top spots unfilled "a significant deterrent to our best reaction."
"I would say it's crucial that the new administration put a priority in getting HHS fully staffed," Leavitt said in a Monday teleconference. "The top 20 HHS officials are on vacation or being held by acting personnel. The secretary of HHS is the key player throughout the federal government in a pandemic or natural medical disaster. Some concentrated effort needs to be made to resolve that."
Vacant High-Level Health Posts and Federal Swine Flu Response
With 40 confirmed cases of swine flu in the United States and no vaccine available, federal officials are gathered today at an HHS command center, where health officials are using giant flat screens to track the disease. At the same time, CDC and FDA labs, also under the purview of HHS, are working to develop a "reference strain" of the virus that can be used for vaccine production, according to a top federal health official.
Meanwhile, Sebelius is not yet cleared to lead the department. Her nomination came late because she was Obama's second pick for the position; the president first picked former Sen. Tom Daschle, who later withdrew from consideration.
At the CDC, Dr. Richard Besser is temporarily at the helm until an official replacement for former director Julie Gerberding is selected. Today Besser was front and center telling Americans about precautions they can take to stop the spread of the virus, such as washing their hands, staying away from crowded places and staying home if they feel ill.
"What I want people to understand is that we're concerned," Besser told "Good Morning America" today. "People should be concerned. We'll tell you what we know when we know it."
The FDA also lacks a permanent leader, with Joshua Sharfstein in charge until Obama's pick, Margaret Hamburg, is confirmed by the Senate.
It also remains unknown who will fill the surgeon general post now that Dr. Sanjay Gupta, Obama's unofficial pick for the job, also withdrew from consideration.
Still, some said that while there's no doubt it would be best to have leaders in place, there is nonetheless a road map in place in case problems like this one arise.
At George Mason University, public policy professor James Pfiffner told ABC News career employees just below the top tier are well-equipped to confront swine flu and "have the expertise to do this."
Pfiffner also said he thinks there could be a plus side to the high-level vacancies because without political appointees in place to lead HHS and CDC, "the link between the (president) and the career people is short."
"I'm not really concerned about the fact that those three positions are open at this point," said ABC News' medical consultant Dr. Tim Johnson, adding that federal health officials are coordinating their response according to policies already on the books.
"I think they are rudderless in terms of making policy, dealing with the political issues that surround them, including health care reform," Johnson said today. "I don't think that can be said about swine flu."
"The good news is since the SARS and avian flu episodes five years ago, our public health structure is in much better shape than it was then," Johnson later said.
Leavitt, too, admitted that, "Those spots are occupied at this moment by some very capable people.
"Again, the thing that distinguishes a pandemic is the duration and the breadth," he added. "This is not a sprint. It becomes a marathon response, and permanent leadership is necessary."
On Capitol Hill, lawmakers have swiftly scheduled hearings for later this week to assess swine flu developments and help determine what's next for federal response.
ABC News' Jake Tapper contributed to this report.