Federal officials Tuesday sought to assure Americans they are taking aggressive action to respond to the swine flu outbreak in the United States.  Their testimony before a Senate panel came as senators confirmed President Barack Obama's choice to head the Health and Human Services Department, which will play a key role in implementing the government's response to the disease.  

Senator Tom Harkin, an Iowa Democrat and chairman of an Appropriations subcommittee that deals with health issues, held the first of a series of congressional hearings this week on the swine flu outbreak:

"There is a lot of anxiety, understandably so, among people as to where we are in this, what's the threat, where we go from here," said Senator Harkin.

Soon after the hearing began, President Barack Obama sent a letter to Congress asking for an additional $1.5 billion to strengthen the country's response to the outbreak.  The money would fund new medical equipment and production of a vaccine.

Dr. Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases at the National Institutes of Health, told the Senate panel that efforts are already underway to find a vaccine:

"We are proceeding along the line that is a step-by-step process of getting a vaccine against this particular virus," said Dr. Fauci.

Senator Kay Bailey Hutchison, a Republican from the U.S. border state of Texas, asked why the border could not be closed to help prevent the spread of the swine flu into the United States from Mexico, where scores of people have died from the disease.

Rear Admiral Anne Schuchat, the Center for Disease Control's interim science and public health deputy director, said there are more effective ways to curb the spread of the virus.

"Based on the pattern of the illness that we are seeing here in the United States, we do not think that this virus can be contained, that we can stop it at the border," said Admiral Schuchat. "But we do think we can reduce the impact of its spread, and we can reduce the impact of health."

She reiterated suggestions from other U.S. health officials that schools be closed if cases of the flu are discovered there and that those infected stay home from work or school.

Meanwhile, late Tuesday, the Senate confirmed Kansas Governor Kathleen Sebelius as Secretary of Health and Human Services, the last member of President Obama's cabinet to be approved by the Senate.

The vote was 65 to 31, with many Republicans voting against Sebelius because of her record in support of abortion rights.   

Among them was Senator Tom Coburn, an Oklahoma Republican and a physician:

"I think there is a critical defect in this nominee, whereas if you are going to be charged with the health and the services of humans in this society, that you are confused on this very issue of transparency and accountability of taking the life of an unborn child," said Senator Coburn.

But Sebelius' supporters argued that her confirmation was important in light of the swine flu outbreak.

Senator Mark Warner is a Virginia Democrat:

"It is essential for the health of the nation that President Obama has in place and the nation has in place a strong Secretary of Health and Human Services to make sure that our federal efforts on this potential pandemic are ably coordinated," said Senator Warner.

President Obama nominated Sebelius after his first choice for the post, former Senator Tom Daschle, withdrew in early February over a controversy relating to unpaid taxes.