SIOUX CITY -- As expected, the H1N1 influenza virus threat appears to be easing among children but increasing among adults. Still, children continue to be at risk and should be among the first to be vaccinated, a state health official said Thursday.

"I think we're seeing the natural progression of this virus in the community," said Dr. Patricia Quinlisk, medical director of the Iowa Department of Health. "It's not doing anything we think is totally off-the-wall. It's acting the way we'd expect a bad seasonal flu to be from the standpoint of how it transmits in the community."

That's why the Siouxland District Health Department will be offering an H1N1 vaccination clinic for people who live with or care for infants younger than 6 months of age and children ages 6 months through 4 years Saturday from 9 a.m. to noon at North Middle School.

"Children are still in the priority groups and that's what we're targeting Saturday," said Chuck Cipperley, deputy director for the Siouxland District Health Department. "Across the state they're (the Iowa Department of Health) seeing older adults becoming affected and we have had some deaths."

State health officials said Wednesday that a 30-year-old Monona County resident was one of four Iowans to die recently from H1N1 influenza virus. The resident was the only one of the four who did not have a medical condition increasing the risk of H1N1 complications.

Eleven people, including one child, have died from H1N1 in Iowa, according to health officials.

Quinlisk said it's not uncommon to see parents getting sick and spreading it to others if there are high levels of the illness in children. "We've known for years that schools are one of the major places where viruses are transmitted," she said.

Meanwhile, the Sioux City Community School District is beginning to see a decline in total absences.

"We have seen a decrease (in illness) in all of our schools," said Alison Benson, spokeswoman for the district.

But people should still take precautions against spreading or contracting the virus and children should still get vaccinated, Quinlisk said. Quinlisk said most adults are not in high risk groups and are unable to receive the vaccine at this time.

"We're trying to vaccinate those at risk from dying from the (H1N1) flu," she said. "At some point, we will start opening (the vaccine) up to older people, but right now we're not doing that."