Idaho’s polio vaccination rate is low and — over the past decade — falling

The Gem State’s kindergarten polio immunization rate is just above ‘herd immunity’ threshold

By: - July 25, 2022 4:25 am
Photo shows a girl lying on a table in a home, while a doctor performs a muscle tone evaluation test on her to check for damage from polio infection

This historic image depicts an Epidemic Intelligence Service (EIS) officer, performing a muscle tone evaluation test on a young patient, to determine if the girl had experienced any paralytic effects, as a result of a polio infection. (Courtesy of the CDC)

Health authorities in New York on Thursday reported the first case of polio in the U.S. in a decade. The patient was unvaccinated and was paralyzed by the viral disease, according to news reports.

While there have been no cases reported in Idaho, the state’s polio vaccination rates have slipped in recent years — leaving more people at risk, were the poliovirus to find its way to Idaho.

Federal estimates show that 86.6% of Idaho kindergarteners were up to date on their polio vaccinations in the 2020-2021 school year. That was the lowest rate in at least a decade and fell short of the U.S. median rate of 93.4%.

Idaho has one of the most liberal vaccination exemption laws in the nation — allowing students to be exempt from any immunization for any reason. It also requires schools to tell parents that they don’t have to immunize their children to enroll them in school.

Idaho’s school immunization report for 2018 through 2022 shows a steady and significant drop in adequate immunization for children.

The highest rates of polio vaccine exemptions in Idaho are, by far, among kindergarten students enrolled in homeschool programs, such as the Idaho Home Learning Academy, which is based in Oneida County in southeast Idaho but whose students are statewide.

The highest rate of up-to-date polio vaccination are in Bear Lake, Jerome and Power counties. The lowest rates are in Bonner, Boundary and Shoshone counties.

Four years ago, about 85.6% of children entering kindergarten were up to date on their immunizations overall, according to data provided by the Idaho Department of Health and Welfare and Idaho Immunization Program. That rate fell to 80.7% in the most recent school year.

Parents or guardians of about 9.3% of Idaho's kindergarteners submitted a vaccine exemption for the child, for non-medical reasons in the most recent school year, up from 7.4% four years ago.

The reports show similar trends for students through the seventh grade.

Still, parents and guardians overwhelmingly have chosen to get their children vaccinated, on the four-dose immunization schedule recommended by pediatricians: at 2 months, 4 months, 6 to 18 months, and 4 to 6 years old.

Public health experts recommend polio vaccination rates of at least 80% to 85% of the people in a community. That’s when a community can achieve ‘herd immunity’ — a cocoon of protection that vaccinated people give to babies and children who don’t yet have their own immunity to the poliovirus. That cocoon also protects people who have compromised immune systems.

photo shows two children walking with braces and a handrail as a physical therapist watches over them
This 1963 image depicted a physical therapist, who was assisting two polio-stricken children that were holding on to a handrail, while they exercised their lower limbs, by keeping a beach ball suspended between their upper bodies. (Charles Farmer, courtesy of the CDC)

Polio is a potentially disabling and life-threatening disease caused by the poliovirus, which spreads from person to person and can infect and injure the spinal cord.

The disease was eradicated from the U.S. in the decades following the creation of an inactivated polio vaccine in the 1950s.

Most people recover from a polio infection, but others are left with permanent physical disability. Some become paralyzed and unable to breathe on their own.

A portion of people who recover from polio go on to develop post-polio syndrome decades later, experiencing symptoms of polio like worsening muscle weakness or trouble breathing.


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Audrey Dutton
Audrey Dutton

Audrey Dutton, senior investigative reporter, joined the Idaho Capital Sun after 10 years at the Idaho Statesman. Her favorite topics to cover include health care, business, consumer protection issues and white collar crime. Before coming home to Idaho, Dutton worked as a journalist in Minnesota, New York, Maryland and Washington, D.C. Dutton's work has earned dozens of state, regional and national awards for investigative reporting, health care and business reporting, data visualization and more.