Napolitano: U.S. expected pandemic alert

WASHINGTON, June 11 (UPI) -- U.S. officials expected the World Health Organization to declare the H1N1 flu outbreak a pandemic, two Cabinet officials said Thursday.

"Once we saw how fast this virus was spreading, we activated our pandemic plans and started doing all the things we needed to do to keep the public as safe and secure as possible," Health and Human Services Secretary Kathleen Sebelius said in a joint statement with Homeland Security Secretary Janet Napolitano.

The WHO declaration Thursday reminds the world that "flu viruses like H1N1 need to be taken seriously," Sebelius said.

While the United States hasn't seen the large number of severe cases other countries have, Sebelius said, "things could possibly be very different in the fall ... and we need to start preparing now in order to be ready for a possible H1N1 immunization campaign starting in late September."

Napolitano said the U.S. response to the H1N1 outbreak in April was with the presumption that a pandemic was likely.

"We acted aggressively to stay ahead of the virus as it spread across the country," she said. "Now our challenge is to prepare for a possible return in the fall."

President Barack Obama always treated the H1N1 outbreak seriously, Deputy White House Press Secretary Bill Burton said.

"What the World Health Organization has done today is more an issue of geography than intensity.

Burton said. "And so our response will be as aggressive as it has been in making sure we're doing everything possible to mitigate its spread."