In this Jan. 29, 2015, photo, pediatrician Charles Goodman vaccinates 1-year-old Cameron Fierro with the measles-mumps-rubella vaccine, or MMR vaccine, at his practice in Northridge, California. (AP Photo/Damian Dovarganes)

TWith just days left in the Colorado Legislature, an important bill that would have improved the state’s dangerously low vaccination rates died in the Senate.

Senate leadership said it wasn’t on their “must do” list, and Republicans seemed ready to try to stop the measure, based largely on philosophical ideology and partly on misinformation about what the bill does.

But make no mistake: While the politics around this bill ultimately killed the measure, the science surrounding it is strong.

This bill was killed in the midst of a nationwide measles outbreak, a fact made more troubling by Colorado’s dismally low vaccination rates. For the 2017-18 school year, Colorado ranked last when it comes to vaccination rates for kindergarten-age children, with a coverage rate of only 88.7% for two doses of MMR.

We need 95% coverage to prevent a measles outbreak. While the difference may seem small, because measles is so contagious, maintaining vaccination coverage of 95% or higher is crucial. It’s the difference between sickness and health for infants, those who have compromised immune systems and pregnant women.

Jessica Cataldi
Sean O’Leary

Vaccines are one of the greatest successes of our time – reducing illness, medical costs and emotional heartbreak for countless families. Thanks to our remarkably successful vaccination program, every year, 42,000 lives are saved in the United States alone.

Vaccines have eradicated smallpox, eliminated polio from the Western Hemisphere – it’s on the verge of complete eradication – and reduced disability and suffering from infections caused by measles, diphtheria and whooping cough.

Yet, vaccines are victims of their own success and, lately, of misleading information not only about their safety and effectiveness but also about important public health policy.

Vaccines held to a higher standard than other medicines

Because they are given to healthy people, vaccines are held to a much higher safety standard than typical medicines.

In fact, vaccines are among the most thoroughly tested and studied medications that we have. Before being approved by the FDA and recommended for use, new vaccines undergo extensive testing for safety and effectiveness on their own and in combination with existing vaccines in the schedule. Additions to the vaccine schedule are reviewed and recommended by the American Academy of Pediatrics, the American Academy of Family Physicians and the Centers for Disease Control and Prevention.  

After a vaccine is put into use, there are several robust systems in place that continually monitor the safety of individual vaccines and the vaccine schedule. 


To protect the most vulnerable people in Colorado, such as young infants and people with certain conditions who can’t vaccinated, all of us who can get fully vaccinated, must. While the overwhelming majority of Colorado children are vaccinated, a small percentage are not, and in this case, that small percentage matters.

When the number of unvaccinated children is very small, the misinformed choices these parents are making generally only puts their own children at risk. When that percentage rises above a certain threshold, though, it puts the rest of us at risk, particularly our most vulnerable. Unfortunately, that’s where we are in Colorado in 2019.

In the United States, we are able to achieve very high vaccination rates in part because of school and child care entry laws saying that children must be vaccinated to attend school. It’s part of the social contract.

There are exceptions. Children with medical conditions that don’t allow them to be vaccinated can get a medical exemption. These are rare.

Exemptions correlate with higher rates of preventable diseases

Colorado, along with 16 other states, also allows religious and personal belief exemptions to vaccination. States that allow religious and personal belief exemptions have higher rates of exemptions and lower vaccination rates.

We also know that the easier it is to obtain one of these non-medical exemptions, the lower the vaccination rates, and the higher the rates of vaccine-preventable diseases like measles and whooping cough.

Right now the process to claim a non-medical exemption in Colorado is among the easiest processes in the country. Right now, it is far easier for a parent in Colorado to choose not to vaccinate than it is to follow the vaccine schedule recommended by their pediatrician or family doctor.

The combination of the lowest vaccination rates and the easiest exemption process in the United States is a perfect storm for setting Colorado up for more and more outbreaks of entirely preventable diseases. It is clear that the time to act is now.

We backed House Bill 1312, which would have formalized the state’s exemption process while preserving parental choice. Under the measure, parents claiming a non-medical exemption would have taken a form, in person, to a local public health agency the first time an exemption is claimed.

This component is important because research shows that having a more formal process — even including this one small step — will also help improve our vaccination rates.

A plea for lawmakers and health officials

We urge lawmakers and government officials to continue to prioritize this issue given Colorado’s dismal vaccination rates.

Diseases quickly become outbreaks when we don’t work together. And misinformation about public health issues is dangerous as well. It has been deeply disturbing to see lawmakers rejecting science and questioning the safety of vaccines, despite hundreds of studies proving otherwise. Such behavior is dangerous, and it hurts children. We expect our elected officials to act responsibly, making decisions based on facts, science and the public’s best interest.

We must work together to prevent an outbreak through improving our immunization policies rather than waiting for an outbreak and responding with emergency measures. Immunization, after all, is not only a personal choice. Whether or not parents vaccinate their children has very real impacts on the rest of the community. 

With the nation’s lowest rate of immunizations for kindergarteners, we are putting Coloradans at needless risk for the spread of serious, preventable, contagious disease. We still must act to implement common-sense solutions to the public from the spread of deadly and debilitating diseases.

For parents seeking reliable vaccine information, we suggest the American Academy of Pediatrics, Vaccinate Your Family, the CDC, and the Immunization Action Coalition. Parents can also ask their child’s school or child care provider about vaccination rates or can find that information on the Colorado Department of Public Health and Environment website.

Jessica Cataldi, MD, and Sean O’Leary, MD, MPH, are pediatric infectious disease specialists. They are part of the Colorado Chapter of the American Academy of Pediatrics.

American Academy of Pediatricians

American Academy of Pediatricians Twitter: @jesscataldi