Children have underdeveloped immune systems.

Because of the that...the Centers for Disease Control is recommending they get a second H1N1 vaccine.

Children 6-months to 9 years of age are recommended to get a second dose of either the nasal spray or shot within a month of getting their first vaccination.

Parents were notified of this when their children received their first vaccination.

A McLean County Health Department spokesperson says that parents have been diligent in making sure their children get the second vaccination within the 21 to 28 day time period.

Immune system protection doubles with the supplemental shot.

"Children at that age have what we call an immature immune system," Sue Albee, Supervisor of Community Health Services, said. "It means they need that second booster dose to get them up to full protection."

"This can be a serious illness, and we want everyone to be vaccinated when they're eligible to receive the vaccine," said Cathy Coverston Anderson, Assistant Administrator of the McLean County Health Department, said.

In the last couple of clinics held by McLean county, about one third of those seeking vaccine were returning children needing a second dose.

Upcomming McLean County H1N1 Clinics:

Tuesday December 8, 3:00pm-6:00pm
Lexington Community Center
207 West Main Street, Lexington, IL

Thursday December 10, 3:00pm-6:00pm
Heyworth Christian Church
308 North Vine Street, Heyworth, IL

Tuesday December 15, 2:00pm-7:00pm
US Cellular Coliseum
101 South Madison Street, Bloomington, IL

Thursday December 17, 2:00pm-6:00pm
St. Patrick's Church of Merna
1001 North Towanda Barnes Road, Bloomington, IL

If you have questions, the Illinois Department of Public Health has a H1N1 flu hotline.

The Illinois Department of Public Health has partnered with the Illinois Poison Center to provide a 24/7 hotline for concerned citizens.

You can call 866-848-2094 (English) or 866-241-2138 (Spanish) to speak to a trained medical professional or visit www.ready.illinois.gov or www.flu.gov for more information.