After a summer of sunny days in the great outdoors, children are back indoors in classrooms filled with their friends. It's nice to have friends close all day, but that nearness also brings risks.

Children share everything from hairbrushes, clothes and toys to colds, the flu and even measles. That's why Idaho requires immunizations for children from child care and preschool through high school.

"Because immunizations have worked, we don't see as much disease as we once did," says Mareva Kammeyer, immunization program coordinator for the Panhandle Health District. "That doesn't mean people should forget how important immunizations are."

Immunizations help prevent contagious illnesses from spreading. In 1950, 319,224 children in the United States had measles and 468 died from it. A vaccine was introduced in 1966 and the following year, the number of cases in the United States dropped to 62,705 with 81 deaths.

By 2007, the measles vaccine was in wide use and only 43 cases and no deaths were reported in the United States. Since then, the spread of misinformation about the vaccine caused a drop in use and the number of measles cases in the United States started to climb again.

Measles and other contagious illnesses that are vaccine-preventable are still troublesome in some countries with low vaccination rates. Air travel enables people from those countries to travel anywhere and sometimes carry such illnesses as measles and chicken pox into the United States.

"I won't be surprised to see some measles cases here in the United States after the Olympics," Kammeyer says. "Measles is prevalent in several of the countries that were represented."

The immunizations required in Idaho help protect children from 11 nasty illnesses. All the illnesses have the potential to cause complications. For example, one in 10 children with measles also gets ear infections and one in 20 gets pneumonia. One or two out of 1,000 die. Pertussis - whooping cough - can cause pneumonia in infants and lead to brain damage, seizures and mental retardation.

In Idaho, vaccine for children is free. Vaccines are available from primary care doctors. Vaccinations also are available at each Panhandle Health District (PHD) office, where nurses are happy to answer questions. At PHD, families pay $14 to $26, depending on the number of vaccinations, to cover the cost of vaccine storage and nurses' time.

Here are the vaccines required.

• Children born on or before Sept. 1, 1999, need

* Four DTaP (diphtheria, tetanus and pertussis)

* One MMR (measles, mumps and Rubella)

* Three polio

* Three Hepatitis B (virus-caused liver disease)

• Children born after Sept. 1, 1999, through Sept. 1, 2005, need

* Five DTaP

* Two MMR

* Three Polio

* Three Hepatitis B

• Children born after Sept. 1, 2005, need

* Five DTaP

* Two MMR

* Four Polio

* Three Hepatitis B

* Two varicella (chicken pox)

* Two Hepatitis A (virus-caused liver disease typically spread through poor hygiene)

• Children heading into seventh and eighth grades need

* One tetanus, diphtheria and pertussis (Tdap - a necessary booster)

* One Meningococcal (to protect from meningitis, an inflammation of the membranes that cover the brain and spinal cord)

PHD provides immunizations by appointment. Call (208) 415-5270. For more information on immunizations, visit www.phd1.idaho.gov or www.cdc.gov.

Cynthia Taggart is the public information officer for the Panhandle Health District. She can be reached at ctaggart@phd1.idaho.gov.