Colorado’s lenient method of allowing parents to opt out of vaccinating their kids for nonmedical reasons means 4.3 percent of kindergartners arrive at school without inoculations required by law.

On Tuesday, a group of health organizations led by the Colorado Department of Public Health and Environment released a report outlining recommendations for making it harder take a pass on vaccination.

Current state policy requires only a parent’s signature to claim a personal, medical or religious exemption, with 93 percent of exemptions taken for personal reasons.

“It’s concerning because vaccines are one of the greatest public health achievements of the 20th century and are estimated to save 3 million children’s lives every year,” said Stephanie Wasserman, executive director of Colorado Children’s Immunization Coalition, one of the groups that helped produce the report.

The report recommends requiring education and counseling prior to exemption and making parents annually sign a Personal Belief Exemption form, with the signature of a medical provider affixed.

Wasserman said implementation of the recommendations is a ways off.

“We’re wanting to disseminate this information and ensure that stakeholders are doing outreach,” she said. “There’s a variety of recommendations that could be implemented through regulations, the state Board of Health or legislation.”

Children’s Hospital Colorado infectious-disease specialist Dr. Sean O’Leary said Colorado is one of 18 states that allow a personal-belief exemption. He said in some ways vaccinations have been a victim of their own success, with the people no longer living in fear of contracting diseases such as polio or measles.

He said schools and day-care centers are the front lines of keeping diseases such as pertussis and chicken pox in check. “The more kids in a school who are unvaccinated, the more at risk that school is for an outbreak of a vaccine-preventable disease,” he said.

Colorado’s lax regulations make accurate tracking of vaccination rates difficult, O’Leary said. A parent enrolling a child in a new school may sign the exemption instead of digging out medical records, even if the child is up to date on vaccinations.

Parents may be skeptical that vaccines are essential, fear they carry their own risk or believe in older vaccines but question newer shots. Others may have concerns about the sheer number of shots and wonder whether the cumulative effect has been studied enough.

Theresa Wrangham, executive director of the National Vaccine Information Center, a nonprofit concerned about the potential side effects of vaccines, worked with the group that issued the report.

“How the recommendations strike me is (that) parents are being told, ‘If you’re taking a personal-belief exemption, then you must not be educated so here, let me educate you,’ ” she said. “That seems kind of coercive.”

Current policy is working just fine, she said, citing a Centers for Disease Control and Prevention report showing that this year, exemptions in Colorado dropped at the fourth highest rate in the country.

However, an August CDC report showed Colorado had the lowest median vaccine rate in the U.S., with almost 17 percent of kindergartners unvaccinated. Mississippi has the best vaccination rate, 99.9 percent, according to the CDC.

Austin Briggs: 303-954-1729, abriggs@denverpost.com or twitter.com/austinbriggs10