When epidemiologist Sophia Newcomer tries to evaluate how well Montana might be able to ward off the measles outbreak spreading across the U.S., she doesn’t have much data to work with.

A federal state-by-state survey last year showed that just over 86% of Montana’s 2-year-olds had recently received the measles, mumps, and rubella immunization. That figure has decreased in recent years, according to earlier surveys, and Newcomer, an associate professor at the University of Montana, said the latest rate is “well below” the ideal 95% threshold for community protection against highly contagious diseases.

But beyond that statewide estimate, information about Montana’s local and regional immunization trends is hard to come by. State officials no longer collect aggregated vaccination reports from schools and child care centers, or the included data about medical and religious exemptions. The administration of Republican Gov. Greg Gianforte discontinued the practice after he signed a 2021 bill striking the requirement.

The last of the localized reports were from the 2018-19 school year, before the disruptions of covid-19. Without the information, Newcomer said, local and state officials have struggled to strategically prevent the spread of vaccine-preventable disease.

“State averages are helpful, but really drilling down to county level or smaller geographic levels are really what we need to assess risk of outbreaks,” she said.

Montana is the only state that no longer collects immunization reports from local schools, creating a data gap for the Centers for Disease Control and Prevention. The information shortage also affects city and county health officials who may not have their own data-sharing agreements with school districts.

Supporters of the 2021 measure to stop collecting data said they were aiming to protect students’ personally identifiable information and medical records and did not intend to cancel the reporting system in its entirety.

“I wasn’t trying to bomb the system. I was just trying to make sure children had their privacy respected,” said Jennifer Carlson, a former Republican legislator and the sponsor of the bill the state health department cites as the reason for discontinuing the data collection.

State lawmakers are considering a bill to undo the 2021 policy, while keeping privacy protections for individual student records. After stalling earlier this session, the Democratic-sponsored HB 364 advanced in March with bipartisan support, clearing the House with a 66-31 vote.

The bill, sponsored by Democratic Rep. Melody Cunningham, has also received support from the state health department, an agency within the Gianforte administration.

Republican Rep. John Fitzpatrick said that he believes the bill is good policy for the state.

“It’s important that public health authorities have access to aggregate information so they can track where vaccinations are not being used,” he said.

Montana hasn’t confirmed a case of measles since 1990. But with more than 480 cases reported across Texas, New Mexico, and 17 other states, one child confirmed to have died from the disease, and another death under investigation, Newcomer said she and other disease experts are “on edge” about Montana’s defenses. Three cases have been confirmed in March south of Calgary, in the Canadian province of Alberta, which shares a border with Montana.

“I like to say that when vaccination rates drop in a community, it is not a question of if. It’s a question of when measles is going to come, because it is so incredibly contagious,” said David Higgins, a pediatrician and researcher at the University of Colorado Anschutz Medical Campus.

Higgins used to work in Montana when the law requiring schools and state officials to share data was still in place. He said he’s disappointed in the 2021 rollback, given how outbreaks begin at the hyperlocal level.

“When community leaders don’t have a good understanding of the local level of vaccination and community immunity, that’s a significant challenge,” Higgins said. “They’re hamstrung without having that data readily available.”

Measles is one of the world’s most contagious diseases, according to the World Health Organization, much more so than covid. It can be very dangerous, especially for infants and children under 5 who have not completed the two-dose vaccination series. Infectious particles can hang in the air and on surfaces for up to two hours. People carrying the virus can spread it up to four days before they begin showing symptoms.

“If we do have a measles case arrive in Montana, and particularly if it arrives in a community that has low vaccination coverage, we’re going to see spread over like a multi-week or even multi-month period,” Newcomer said. “So an unvaccinated person can get sick simply by going into a school, store, or home where someone infected with measles recently was.”

The infection can have short-term and long-term consequences for people who are not immunized, including encephalitis, pneumonia, deafness, blindness, and death. State and community health departments have been advertising free MMR vaccinations at clinics throughout the state for anyone who needs them.

While HB 364 is aimed at increasing data collection, other vaccine measures in the state legislature are advancing that would make it easier for children to be exempted from standard immunizations required to attend schools or child care centers.

A recent version of SB 474, which has been amended several times, would create an “informed consent” exemption in which a parent or guardian could decline immunizations for school-age children without stating a reason.

Supporters of the bill said that some families struggle to receive exemptions on the grounds of religious beliefs or medical causes and want broader flexibility to opt out of requisite vaccinations against measles and other infectious diseases, such as pertussis. According to Montana’s most recent reporting, from the 2018-19 school year, roughly 3% of children in public schools had a religious or medical exemption.

SB 474 also would strike another part of state law that allows schools and day cares to deny admission to children because they are unvaccinated, an exemption included in a 2021 law aimed at protecting unvaccinated people from discrimination. The lawmaker sponsoring the current bill called the carve-out for schools and day cares an “aberration” in Montana law.

“There’s no reason that they should be discriminating based on vaccine status,” Republican Sen. Daniel Emrich said during a March debate on the Senate floor.

Emrich and others framed the bill as enabling individual decision-making around vaccinations based on how well a parent knows their own child.

“Vaccines are pretty effective,” Emrich said. “If you’re concerned about unvaccinated children, you have the option to get your kid a vaccine to protect them in whatever way you want. This bill is really about choice.”

During the debate, opponents of the bill contended that the lower Montana’s overall immunization rate drops, the more at risk many community members are, including those who, because of age or medical issues, can’t be vaccinated.

Sen. Cora Neumann, a Democrat representing Bozeman, said that vaccinated Montanans, including children, are acting as “shields” against contagious diseases like measles and pertussis. But if vaccination rates continue to drop, Neumann said, that protection will only get weaker.

“We just saw a kid die of measles [in Texas]. It’s going to continue, and it is going to be scary. It is going to be deadly,” Neumann said. “It feels like a luxury right now. We can choose. It is not going to be if we continue down this path.”

The bill passed the state Senate on a 28-21 vote. It is now under consideration in the House.

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