The newest report on vaccine-preventable diseases in Colorado’s children was released today by the Colorado Children’s Immunization Coalition and Children’s Hospital Colorado, and the results are sobering. After days of headlines touting that Colorado’s kindergarteners have the lowest measles vaccination rate in the country at 81.7 percent, the overall view on the state’s immunization records offers similar findings. According to the report, Colorado ranked 45th among U.S. states for childhood vaccinations in 2013, with one in four kids considered “under-immunized”—meaning they have received less than the recommended doses of vaccines approved by the Colorado Board of health—at 36 months of age.

We spoke with Dr. James Todd, director of epidemiology at Children’s Hospital Colorado and co-author of the report, for his take on the findings, the reasons the state is lagging in immunizations, and what parents can do to protect their children even if they are up-to-date on vaccines.

5280: Did you see an outbreak of vaccine-preventable disease coming?

Dr. James Todd: We could have predicted this, even if I just sat at my desk and looked at the vaccination numbers. It’s clear that our vaccination rates have been pretty stable, and not very good in Colorado. There are many children who are not fully vaccinated or [not] being vaccinated on time. This raises a couple of issues. We are seeing kids being admitted to the hospital for vaccine-preventable diseases like pertussis and influenza. Measles is just now raising its ugly head. With highly contagious bug like measles, it only takes a few unimmunized kids to start spreading. There are lots of other [diseases] that could become a problem.

Who should be worried about the rise in vaccine-preventable diseases?

Young children are the most vulnerable, but they are often getting it from older people who have traveled and brought it back. But a lot of these diseases still exist in our community all the time. If Grandpa gets shingles, that’s the Chicken Pox virus that’s reactivating in our bodies. Grandpa could be exposing his grandchildren [or their] friends who didn’t get vaccinated.

What is the risk to parents of young children who have only received one vaccine that requires multiple doses or a booster?

The schedule is designed to protect Colorado kids for the degree of likelihood that they may encounter certain diseases. We balance the number of doses and the need for boosters based on your risk of exposure. Because we dramatically reduced the exposure risk for a number of these diseases, the current schedule is felt to be adequate to protect children. If they were to go to the Philippines, where measles is rampant, we’d recommend that he or she get a booster early. Now, we have to worry about Disneyland.

Why do you think Colorado parents aren’t vaccinating their children?

You see certain groups that oppose vaccinations for religious reasons. In Colorado, that’s a rare exception. The much greater exemption is the personal-belief exemption, or the people who are adopting alternative vaccination schedules. The interesting thing is that parents who are choosing not to vaccinate their children—or not vaccinate them on time, which can be just as bad—tend to socialize together.

In your opinion, should unvaccinated students be allowed to attend school?

Unvaccinated kids should not be allowed to attend school. If those kids go to school together, all it takes is one kid to introduce one case and a whole bunch of kids are at risk.

How can parents be proactive about protecting their children in a school or daycare situation?

Part of Colorado House Bill 1288 passed during last year’s legislature requires licensed daycares and schools to provide vaccination statistics when asked. Parents with vaccinated children or with high-risk children should be asking daycares and schools if all the kids are vaccinated. The great majority of people are protecting their kids with vaccines, and they should be speaking up.

Due to the contagious nature of these diseases, especially measles, this really expands beyond schools to any pocket of unvaccinated children with like-minded parents. Is that correct?

These parents are putting their children at risk, but they are also putting other children at risk. When your vaccination rate falls, it increases the likelihood that it will spread from the little community who has chosen to be unvaccinated to the child who couldn’t get a vaccine for medical reasons or has an underlying condition and may be more vulnerable to getting that disease. There are going to be people out there who will be at risk and can’t be vaccinated for legitimate reasons—like immune disorders or chemotherapy treatments. The large number of people choosing not to be vaccinated puts everyone at risk.

What is your suggestion to improving the immunization rate in Colorado?

I don’t have much hope for the political process, so people need to ask if they really want their kid going to a playgroup where they know parents are choosing not to vaccinate their children. Things will change when the 90 percent of people who believe in vaccinating their kids, and doing it on time, start speaking up and saying that they don’t want their kids exposed to measles, pertussis, and other preventable diseases. They can’t let a very vocal group of people who are basing their beliefs on anecdotes, rather than science [put their children at risk]. These kids are exposed, and it’s only a matter of time when one will come down with a terrible disease. Then parents will really regret that they didn’t vaccinate their child. All it has to do is catch fire in a group of unvaccinated kids.

Follow assistant editor Lindsey R. McKissick on Twitter at @LindseyRMcK.