If an influenza pandemic comes, Utahns would get minimal or no warning, would have to wait six to eight months for a vaccine, could expect two waves of illness and 4,000 deaths.

That "optimistic caution" was given Thursday by Utah health and agriculture administrators who unveiled the state's pandemic response plan.

Although seasonal flu is not life-threatening for healthy individuals, "pandemic influenza is altogether a different matter," said Dr. David Sundwall, executive director of the state Department of Health. "It occurs when a new strain of influenza emerges that can be transmitted easily from person to person or for which people have no immunity. Unlike season flu, it can kill the young, healthy, as well as the frail and sick."

The plan would be the response to any pandemic, be it one that many health experts say has been due for some time in the world or an outbreak of bird flu, which is caused by a new strain of virus (H5N1) linked to recent human deaths in Southeast Asia but so far shows no sign that it can be spread person to person.

"We do know a pandemic influenza will occur someday," said Dr. Robert Rolfs, state epidemiologist with the health department. "We are concerned that this avian influenza will do that, but we don't know if that will happen or not."

For now, Utahns should be focusing on battling the seasonal flu. "That's what we really should be worried about today," Sundwall said, encouraging Utahns to get flu shots.

The same cautions people practice when protecting themselves from the seasonal flu — staying home from work or school when sick, covering their mouths when coughing or sneezing and washing their hands regularly — also protect during a pandemic, because the two spread similarly.

Utahns can also prepare for a pandemic by storing necessities.

"It is possible that people would end up being confined in their home if they became ill or had been exposed," Rolfs said. "We decided that in order to limit spread, (infected) people should stay home for a few days. So they need to have supplies to be able to stay home if that happens."

Limiting the spread through isolation is crucial, which is why treatment will be handled on a regional and community level, Sundwall said. But, he noted, a large outbreak would overwhelm the health-care system.

According to the Utah Pandemic Influenza Response Plan, if an outbreak the magnitude of the 1918 pandemic were to occur, roughly 1 million Utahns would become clinically ill, half would require medical care, 15,000 would need to be hospitalized and 4,000 Utahns would die.

Because travel is considered the most likely way an influenza pandemic would arrive in Utah, public health restrictions would include air and group travel, screening people arriving from affected areas and canceling or closing large gatherings sites such as schools.