Bettie Davenport didn't take any chances this time.

At last month's swine flu vaccination clinics in Casper, health workers ran out of doses just as she arrived. So for Thursday's clinic, she came 2 1/2 hours early with a lawn chair and a purple blanket.

"I take care of my great-grandbabies and I prefer to stay on the healthy side for them," she explained as she waited outside Cottonwood Elementary School for the clinic to begin.

The early arrival paid off. Davenport got the third spot in a line that, 45 minutes before the doors opened, already stretched back at least 100 yards.

Health works ultimately vaccinated about 1,000 people against swine flu during clinics at Cottonwood and at Kelly Walsh High schools, according to the Casper-Natrona County Health Department.

As was the case during last month's events, some people endured long waits for a chance to get the vaccine, which is in short supply throughout the United States. Even though 35.6 million doses of the vaccine have been made and readied for distribution, manufactures haven't been able to keep up with demand, according to the Centers for Disease Control.

The limited amount of vaccine has meant only high-risk groups have been eligible to receive it in Natrona County.

But the clinic still had about 100 doses left when it closed at 7 p.m. By the end, the long lines had been replaced by a trickle of people, said health department spokeswoman Jillian Riddle.

Thursday's clinics were the first open to people with chronic health conditions like kidney disease. That drew Casper resident Jan Gillham, who worried a swine flu infection could land her in the hospital because of her diabetes.

She arrived at Cottonwood more than two hours early with a chair and a Good Housekeeping magazine. Despite the long wait and blustery conditions, she remained upbeat.

"I'm a pretty patient person," she said.

The clinics were also open to pregnant women, people between 2 and 24 years old and infant caregivers. Those groups are considered to be among the most vulnerable to the H1N1 virus.

Babies haven't been eligible for either of the first two rounds of public clinics in Casper. However, a clinic specifically for children between 6 and 35 months will be held today at the health department.

A third round of public clinics has been scheduled for next month. Local health officials haven't announced which groups will be eligible to receive the vaccine at those events.

Flu activity in Wyoming is widespread, according to state health officials. More than 600 cases of swine flu have been reported, but the actual number of infections is likely much higher since most people don't seek treatment or get tested.

Since swine flu appeared in Wyoming earlier this year, four people have died after contracting the virus.

Wyoming usually experiences between two and 11 flu-related deaths annually, health officials say.

Reach reporter Joshua Wolfson at (307) 266-0582 or at josh.wolfson@trib.com. Visit tribtown.trib.com/JoshuaWolfson/blog to read his blog.

Upcoming swine flu vaccination clinics

A clinic for babies will be held from 8 a.m. to 4 p.m. today at the Casper-Natrona County Health Department. Children between 6 and 35 months can participate.

Another public clinic is scheduled for Dec. 3 at Cottonwood and Kelly Walsh.

For more information, visit www.casperhealth.com.