County officials believe the line at the swine flu vaccine clinic at Pioneer High School exceeds the number of wristbands still available to get the vaccine.

They are encouraging no more residents to head out to the vaccine clinic today.

By around 9:30 a.m., about 600 wristbands - each wristband represents one dose of the vaccine - were still available, but 800 to 900 people were standing in line. The line stretched from Pioneer High School’s main entrance, around its parking lot to Main Street.

The first people in line arrived about 5:45 a.m.

The clinic, to be held from 9 a.m. to 2 p.m. at the high school, is the county's third.

The next available clinic for the H1N1 flu vaccine will be next Sunday, Nov. 22 at the Eastern Michigan University Convocation Center. A time for that clinic has not yet been announced.

It is believed demand is so high, in part, because the county opened up availability of the vaccine to more priority groups.

Those eligible to receive the vaccine now includes all young people ages 6 months through 24 years of age.

It also includes individuals who are between the ages of 25 years and 64 years who have underlying health conditions that put them at greater risk of having complications from the flu. Examples of those underlying health conditions include chronic lung disease, a weakened immune system, cancer, diabetes, kidney or liver disorders, cardiovascular disease and other conditions.

Priority groups for the vaccine clinic still include pregnant women, caregivers of children younger than 6 months old and health care workers. Those who are 65 and older are not in the Centers for Disease Control guidelines to receive priority in receiving the vaccine.

Tina Reed covers health and the environment for AnnArbor.com. You can reach her at tinareed@annarbor.com, call her at 734-623-2535 or find her on Twitter @TreedinAA.