Calling the shots.

• Author: Goodwin, Kristine
• Position: TRENDS - Vaccine laws for schoolchildren

Tis the season when flu, colds and other illnesses keep kids home from school, and while many illnesses are routine and unavoidable, others are serious and often preventable.

For states, they're also costly.

In 2012, for example, 414 Colorado children, most of them under age 4, were hospitalized with vaccine-preventable diseases, such as pertussis and varicella, resulting in estimated hospital charges of $26.6 million and other related costs, including missed work days for parents.

In Colorado and other states, lawmakers have debated vaccine laws for schoolchildren in an effort to reduce the number of avoidable hospitalizations and limit disease outbreaks and suffering, while also respecting parents' rights to make heath care choices for their children.

All states require kids to have certain shots to enroll in school so that preventable diseases don't spread, but they do grant exceptions for medical reasons, such as a weak immune system. Additionally, most states allow exemptions based on religious grounds, and at least 20 states allow parents to refuse vaccinations for their children for personal or philosophical reasons. Some parents believe vaccines don't help, or that shots can make their kids sick or cause certain disorders. Others consider mandatory vaccinations government overreach.

It's a tough conversation for legislatures because it involves competing rights and values and deciding whether government or parents have the final say. "Exemptions to school immunization requirements continue to be an issue for discussion and debate in many state legislatures," say authors of a 2014 study published in the Journal of the American Medical Association.

Between 2009 and 2012, lawmakers in 18 states introduced 36 bills involving vaccine exemptions, 31 of which would have made...