Health officials are targeting more than 400,000 high-priority South Dakotans in a vaccination outreach to fight an expected mix of regular influenza and the new H1N1 virus that could infect up to 30 percent of the state population.

Gov. Mike Rounds joined state and local health officials Thursday in Rapid City and Sioux Falls in urging South Dakotans to get vaccinated and take steps - including frequent hand washing, covering coughs and staying home when sick - to prevent the spread of flu viruses. The H1N1 virus, commonly known as swine flu, was detected in South Dakota in May and 79 cases - 25 of them in Pennington County - have since been confirmed.

With the main flu season still months away, the early education campaign is focused on H1N1 in hopes of holding the infection rate to less than the potential 30 percent.

"The whole goal here is to slow down the spread of the H1N1 influenza bug," Rounds said during a news conference at the Rushmore Plaza Civic Center.

Pregnant women and children up to 18 years old are particularly vulnerable to the H1N1 virus, which is expected to mix with the regular season flu strains to create a flu season with impacts crossing virtually all age groups, Rounds said. H1N1 isn't considered more virulent than regular seasonal flu strains, but all types can kill.

"You can say it's just the flu, but every single year with the normal flu, people die and people get seriously ill. So it is dangerous," he said. "We can save lives in South Dakota this year (with people) who would die if we didn't get the word out."

South Dakota will benefit from a $9 billion congressional appropriation aimed at making a plentiful supply of H1N1 vaccine available across the United States, probably by mid-October. The first round of shots will focus on children, young adults and pregnant women. It will be followed by a booster shot in three to four weeks.

The booster is needed to make the new vaccine effective in a population that hasn't had one before. Unlike seasonal strains that are particularly hard on the elderly, H1N1 seems to hit hardest in younger age groups, Rounds said. The virus is similar to a flu that circulated in the 1950s, and apparently left older people with some resistance to H1N1. People born after 1957 appear not to have that resistance, he said.

"The younger they are, the more susceptible they are," Rounds said. "So it's very important that we get those young people protected."

The H1N1 vaccines will be provided free, although health care providers may charge an administrative fee. Free inoculation clinics will go into the schools, including higher educational institutions, with the goal of vaccinating as many students as possible. Rounds said seasonal flu vaccines should be available by September. He urged older citizens and other high-risk groups for those strains to get their regular flu shots as soon as possible, then come back later for their H1N1 shot and booster. To be fully protected this year, people will need three shots - the H1N1 and booster, and the seasonal flu shot.

State epidemiologist Kightlinger said people shouldn't worry about getting an early seasonal flu shot and having it lose effectiveness while the flu season is still on. A flu shot in September should last through the season, he said.

Dr. James Keegan of Regional Health Systems in Rapid City said H1N1 has been showing up in local laboratory tests. A group of Black Hills teenagers apparently contracted the flu while attending a youth gathering in New Orleans last month.

Keegan said the symptoms of H1N1 at this point have typically been mild, but that could change to more severe symptoms as the flu season progresses.

Kightlinger said it was unusual to see a flu strain so active through the summer. It's likely that H1N1 will settle in to a more common flu season, as one more strain to fight, he said. Because it's a new virus to most of the population it adds different element to the fight, he said.

"There are a lot of people who have no resistance, and this virus is taking advantage of it," Kightlinger said.

More than half the 79 confirmed South Dakota cases of H1N1 were people under age 20. Eighty percent were under 30 and the oldest was 55.

"Very few old people, elderly people are ill with H1N1," Kightlinger said.

More info

To learn more about H1N1, go to the South Dakota Department of Health Web site: http://doh.sd.gov

Information is also available from the CDC at 1-800-232-4636) on online at http://www.PandemicFlu.gov

Contact Kevin Woster at 394-8413 or kevin.woster@rapidcityjournal.com