XENIA, Ohio -- Hundreds of people lined up at the Greene County Fairgrounds Thursday afternoon to receive an H1N1 vaccine.

The clinic was held from 2 to 7 p.m. and was for priority groups only, which include the following:

* Pregnant women because they are at higher risk of complications and can potentially provide protection to infants who cannot be vaccinated;

* Household contacts and caregivers for children younger than 6 months of age because younger infants are at higher risk of influenza-related complications and cannot be vaccinated. Vaccination of those in close contact with infants younger than 6 months old might help protect infants by “cocooning” them from the virus;

* Healthcare and emergency medical services personnel because infections among healthcare workers have been reported and this can be a potential source of infection for vulnerable patients. Also, increased absenteeism in this population could reduce healthcare system capacity;

* All people from 6 months through 24 years of age

* Children from 6 months through 18 years of age because cases of 2009 H1N1 influenza have been seen in children who are in close contact with each other in school and day care settings, which increases the likelihood of disease spread, an

* Young adults 19 through 24 years of age because many cases of 2009 H1N1 influenza have been seen in these healthy young adults and they often live, work, and study in close proximity, and they are a frequently mobile population; and,

* Persons aged 25 through 64 years who have health conditions associated with higher risk of medical complications from influenza.

The clinic will last until 7 p.m. or until supplies are gone.