Vaccination rates among Iowa school children are dropping. More than four-and-a-half percent of Iowa students had not been immunized against major diseases like polio by last fall. Don Callaghan is the immunizations bureau chief for the Iowa Department of Public Health.

Iowa law requires students enrolled in school to be vaccinated against polio, measles and other diseases, like hepatitis B. Iowa law allows parents to get an exemption for their children because of their religion or for medical reasons. Twenty-seven Iowa schools had fewer than 80 percent of students vaccinated last school year. Five schools had vaccination rates of 50 percent or lower. Callaghan says state officials will be checking immunization records this year, too.

Measles outbreaks are rare in the U.S. because of the vaccination program started in 1963, but Callaghan says the disease is “easily imported.”