WASHINGTON: US President Barack Obama declared the H1N1 flu outbreak a national emergency, giving his health chief the power to let hospitals move emergency rooms offsite to speed treatment and protect noninfected patients.

Some of the 1,200 people who braved rain and 39 degree (3 degrees Celcius) temperatures queue to receive a free H1N1 flu vaccine at Richard J. Daley College in Chicago October 24, 2009. US President Barack Obama has declared 2009 H1N1 flu a national emergency, the White House said on Saturday. [Agencies]

The declaration, signed Friday night and announced Saturday, comes with the disease more prevalent than ever in the country and production delays undercutting the government's initial, optimistic estimates that as many as 120 million doses of the vaccine could be available by mid-October.

Health authorities say more than 1,000 people in the United States, including almost 100 children, have died from the strain of flu known as H1N1, and 46 states have widespread flu activity. So far only 11 million doses have gone out to health departments, doctor's offices and other providers, according to the Centers for Disease Control and Prevention officials.

Health and Human Services Secretary Kathleen Sebelius now has authority to bypass federal rules when opening alternative care sites, such as offsite hospital centers at schools or community centers if hospitals seek permission.

Some hospitals have opened drive-thrus and drive-up tent clinics to screen and treat swine flu patients. The idea is to keep infectious people out of regular emergency rooms and away from other sick patients.

Hospitals could modify patient rules - for example, requiring them to give less information during a hectic time - to quicken access to treatment, with government approval, under the declaration.

It also addresses a financial question for hospitals - reimbursement for treating people at sites not typically approved. For instance, federal rules do not allow hospitals to put up treatment tents more than 250 yards away from the doors; if the tents are 300 yards or more away, typically federal dollars won't go to pay for treatment.

Administration officials said those rules might not make sense while fighting the flu, especially if the best piece of pavement is in the middle of a parking lot and some medical centers already are putting in place parts of their emergency plans.

The national emergency declaration was the second of two steps needed to give Sebelius extraordinary powers during a crisis.