Why Montana Data is Missing From National Childhood Immunization Reports

This story is adapted from the MT Lowdown, a weekly newsletter digest containing original reporting and analysis published every Friday.

A reader pointed out earlier this week that national reports from the U.S. Centers for Disease Control and Prevention on kindergarten vaccination rates have shown what they considered a conspicuous omission over the past three years — a complete absence of data for the state of Montana. Finding their curiosity infectious, we dug in.

We confirmed that, shortly after the onset of the COVID-19 pandemic, Montana had been the only state in the country not to provide federal health officials with aggregated data about the childhood immunizations required of public school students and the exemptions granted to families in certain circumstances. For over two decades, such data has allowed the CDC and others to inform the public about statewide vaccination rates among kindergarteners for contagious diseases like measles, mumps, and whooping cough. It also allows the agency to track long-term trends, including a nearly 3% nationwide decline in MMR vaccinations since 2019.

Montana’s contribution to that data ended in 2021 due to a new law broadening the ability of individuals to secure exemptions to vaccine requirements. While public schools are still required to obtain vaccination or exemption information from incoming students, Montana Department of Public Health and Human Services spokesperson Jon Ebelt said his agency no longer collects that data from schools as that year’s House Bill 334 struck its mandate to do so from the state’s codebook. Ebelt added that DPHHS could not complete its school immunization report for the 2019-20 school year due to COVID-related issues, meaning the last full year of Montana data was 2018-19.

Rep. Ed Stafman, D-Bozeman, introduced a measure reinstating the data reporting requirement during the 2023 legislative session, telling members of a House committee that HB 334’s original sponsor — Rep. Jennifer Carlson, R-Manhattan — had informed him the change was an unintended consequence of her bill’s passage.

“We have a public health emergency, a disaster on our hands, without that data,” Stafman said at the time. “If and when an epidemic breaks out, we don’t have the tools to deal with it.”

Stafman’s proposal failed to make it out of committee, meaning Montana remains the only state absent from the national data.

Public health officials have repeatedly said they rely on K-12 vaccination data to understand how vulnerable communities are to the spread of certain diseases. Sophia Newcomer, a vaccination researcher and associate director at the University of Montana’s Center for Population Health Research, told MTFP that kindergarten vaccination data could help tell healthcare workers where to focus their efforts if, for example, cases of whooping cough begin to rise in a neighboring state. Without it, Newcomer said, Montana is “flying blind” in the face of potential outbreaks.

Newcomer, a mother with school-aged kids, said it’s also important for parents to have information about how many of their kids’ peers are vaccinated. That’s especially true for parents with children who have underlying medical conditions, she said, such as a child undergoing chemotherapy. She added that even children with healthy immune systems can carry diseases like whooping cough home to more vulnerable groups, such as grandparents and infant siblings.

“If we don’t know what vaccination rates are in schools — if we’re not even looking at it — we’re not ready for when we see measles outbreaks occurring in neighboring states,” Newcomer said. “Without knowing what is our level of protection at a community level, what is our level of protection in schools, we’re not ready to respond at that community level.”

A list of bills requested in advance of the 2025 legislative session indicates Stafman is planning to take another run at his effort to require that Montana once again report state-level data on student immunization and exemption rates.