Polio sparks images of a time long past - people in black and white photos wearing leg braces, using crutches, in iron lungs. Not too many years ago, polio terrified people living in the United States. An infectious viral disease that hit all ages, polio killed thousands of Americans every year and left tens of thousands more crippled for life.

At its worst point in 1952, polio killed 3,145 and left 21,269 people in the United States paralyzed to some degree.

Then, a safe and effective vaccine was developed. Dr. Jonas Salk's licensed polio vaccine was so effective that polio cases in the United States dropped by 90 percent - from nearly 58,000 one year to 5,600 the next - after voluntary mass immunizations. With help from a second vaccine and a population determined to protect itself by immunizing, the United States experienced its last polio case in 1979.

Polio is an excellent example of the value of vaccinations. An entire generation never has worried about the crippling disease, at least in the United States.

Somalia isn't as lucky. Seventy percent of Somali children aren't fully immunized and the country is suffering right now through an alarming polio outbreak. A vaccination campaign is ongoing, but the outbreak is a setback to a World Health Organization effort to eradicate polio worldwide.

History has shown that contagious diseases take advantage of low immunization numbers. Measles was declared eliminated in the United States in 2000. It no longer annually spreads around the country. But measles is still common in other parts of the world.

From 2000 to 2010, the United States had about 60 cases of measles per year. People not vaccinated against measles traveled, picked up the viral disease, brought it back to the United States and spread it to other unvaccinated people. In 2011, the number of measles cases in the U.S. jumped to 222 as immunization rates continued to decrease.

Measles causes a fever, runny nose, cough and rash all over the body. One out of 10 children also gets an ear infection and one out of 20 gets pneumonia. One out of 1,000 gets encephalitis and one or two out of 1,000 die.

Unvaccinated children are 30 times more likely to catch measles than vaccinated children are. Before a safe and effective vaccine was developed, the United States had nearly 320,000 cases of measles and 468 deaths in one year. A year after voluntary immunizations began, measles cases in the United States fell to 62,705 and deaths dropped to 81.

After the vaccine was in use for 40 years, the U.S. had 43 cases of measles and no deaths. But as immunization rates recently decreased, the number of measles cases began to increase.

In the United States, vaccines have greatly reduced and, in some cases, nearly eliminated diphtheria, tetanus, polio, measles, mumps, pertussis (whooping cough) and chicken pox.

In Idaho, vaccine for children is free. The only cost is for supplies, storage and nurses' time. At Panhandle Health District (PHD), immunizations for children without health insurance cost $20 per shot per visit with a maximum charge of $60 for three or more shots. The cost for children with health insurance is $20 per shot and PHD will bill insurance.

PHD carries all school-required immunizations for children in its offices. For a list of required immunizations, visit www.phd1.idaho.gov and click on Clinical Services, then Immunizations. For an appointment, call (208) 415-5270. PHD is located at 8500 N. Atlas Road in Hayden.

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