As they confront the growing swine flu crisis, President Obama's administration is attempting to implement a never-before-tested pandemic response plan while dozens of key public health and emergency response jobs in the administration remain vacant.

The president has yet to fill 15 top positions at the health department or name a full-time director for the Centers for Disease Control and Prevention and five more nominations -- including that of former Kansas Gov. Kathleen Sebelius to be HHS Secretary -- are waiting to be confirmed by the Senate, officials at the department said.

The top post at the CDC remains open but is being filled by an acting director. And at the Department of Homeland Security, which is leading the federal government's response to the swine flu outbreak, the functions of nearly 20 senior-level posts are being temporarily performed by career civil service employees.