Expert Commentary

Should states ban religious exemptions for student vaccinations? Researchers weigh in

Three recent studies examine the effectiveness and unintended consequences of banning religious exemptions to childhood vaccinations in California schools.

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(Heather Hazzan, SELF Magazine)

In June, New York became the fifth state to require its schoolchildren to be vaccinated despite their parents’ religious beliefs or philosophical objections.

Amid a surge in measles cases nationwide this year, legislators and community leaders are debating ways to boost the number of kids who are up to date on their school-mandated shots. Many have focused on restricting or eliminating vaccination exemptions based on religion or personal opinions, which are common and have been offered by school districts across the United States for decades.

But three recent academic studies suggest this might not be the most effective way to improve childhood vaccination rates. In fact, the research indicates banning these exemptions could backfire.

Scholars studied student vaccination rates in California, the nation’s most populous state, and discovered that when parents cannot get an exemption based on their personal beliefs, some seek other ways for their children to stay in school while skipping one or more vaccinations. The researchers also learned that while California lawmakers have targeted personal belief exemptions, which are used by a relatively small group of students, a larger group of children is being allowed to enter kindergarten on a “conditional status” basis with incomplete vaccinations.

In 2014 — the year before California passed a law eliminating vaccine exemptions based on personal beliefs, including religious beliefs — 13,254 California kindergarteners used these exemptions to forgo vaccinations. Meanwhile, another 36,411 kindergarteners were admitted to school on a conditional basis, according to the research.

Paul L. Delamater, the lead researcher on one of the three studies and the co-author of another, says helping conditional status students finish getting their shots would be a more effective way to boost vaccination rates than banning personal belief exemptions.

Also, he says, it likely would be easier to encourage the parents of conditional status students to get their kids up to date than it would be to convince parents who want their children to be able to opt out of the vaccine requirement.

“Trying to focus on parents who are not vaccine hesitant first may be a good way forward,” says Delamater, a fellow at the Carolina Population Center who’s also an assistant professor at the University of North Carolina at Chapel Hill. “I think parents with real vaccine hesitancy are going to search for ways to not vaccinate their children.”

All three studies examine vaccination rates among kindergarteners in California, which, in 2015, became the first state in almost 30 years to eliminate non-medical exemptions. The new law, referred to as Senate bill 277, took effect in 2016.

Among their key findings:

  • While the percentage of kindergarteners who were up to date on their shots increased in 2016, the vast majority of the increase was linked to a different change made by school officials. Schools cut back on the number of children allowed to enter kindergarten on a conditional basis.
  • After schools in California did away with personal belief exemptions, they saw a sharp increase in students submitting medical exemptions. The researchers suspect that some parents who could no longer use personal belief exemptions obtained authorization from doctors to skip vaccinations for medical reasons.
  • While a larger share of kindergarteners had all their required vaccinations after Senate bill 277 took effect in 2016, the trend reversed the following year. The drop in up-to-date students, researchers explain, is connected to the spike in children using medical exemptions as well as an increase in the number of kindergarteners enrolled in school who were designated as “overdue” for vaccinations, oftentimes because they had missed a dose of a vaccine. In addition, Senate bill 277 effectively created a new exemption, allowing more than 5,000 kindergarteners in 2017 to forgo vaccinations if they attended a school without classroom-based instruction or had what are called “individualized education plans.”

Delamater says other states can learn a lot from California.

“California has been trying to be very proactive about this via legislation and for us, as researchers, it gives us a very interesting opportunity to evaluate how these big changes in policy relating to vaccinations – how people actually react to that,” he says. “As you’ve probably seen from looking at these papers, it’s not a really straightforward and easy-to-understand thing. There is a lot of nuance to this.”

Chelsea Richwine, the lead author on a working paper from the National Bureau of Economic Research that investigated the effects of Senate bill 277, stressed the importance of kids getting all their required vaccinations. It’s as dangerous for a child to have incomplete vaccinations as it is to skip them altogether, she says.

She recommends restricting vaccine exemptions while also making it clear when and under what circumstances youth should be allowed medical exemptions from one or more required vaccines. In many cases, kids need only to delay vaccinations for a certain period of time, not avoid them completely. Both the American Medical Association and American Academy of Pediatrics support eliminating non-medical exemptions.

In California, lawmakers are considering a bill that would make it tougher for parents to obtain a medical exemption after discovering that some doctors have been distributing large numbers of medical exemptions, some of which might not have been in response to a true medical problem. In San Diego, for example, one doctor has provided almost a third of the 486 medical exemptions used by students in the San Diego Unified School District since mid-2015, according to the Voice of San Diego news outlet.

Under the proposed legislation, the State Department of Health would review vaccination reports from doctors who submit five or more medical exemption forms in a calendar year.

“Exemptions are appropriate in certain circumstances, especially medical exemptions,” explains Richwine, a fourth-year doctoral candidate studying health policy at George Washington University. “I think we have to take a more holistic approach to looking at medical and non-medical exemptions. It’s not an effective policy on its own — if there’s an opportunity to substitute [one exemption for another].”


Below, we’ve summarized the three recent studies that Delamater, Richwine and their colleagues authored. We also included other research we think you’ll find helpful, including a study that finds that the parents who were most likely to file personal belief exemptions before California banned them were white and from upper-income levels.

For journalists interested in comparing state laws on child vaccination requirements, the National Conference of State Legislators tracks which states allow medical and non-medical exemptions.


Associations of Statewide Legislative and Administrative Interventions With Vaccination Status Among Kindergartners in California
Pingali, S. Cassandra; et al. JAMA, July 2019.

For this study, researchers examined the impact that three California initiatives — including Senate bill 277 — had on the vaccination rates of kindergarteners. In 2014, a new state law made it harder for parents to get a personal belief exemption. In 2015, school officials began limiting the number of children they allowed to start kindergarten on a conditional admission basis. Then, in 2016, Senate bill 277 was enacted, eliminating personal belief exemptions.

The researchers find that between 2000 and 2017, 9.3 million California kids entered kindergarten, 721,593 of whom were not up to date on their required vaccinations. During the period the three initiatives were launched, the percentage of kindergarteners with incomplete vaccinations fell. In 2013, 9.84% of kindergarteners were missing some or all school-mandated immunizations. That number dropped to 4.42% in 2016 but then rose slightly to 4.87% in 2017.

Most of the reduction in kindergarteners with incomplete vaccinations is linked to the crackdown on conditional admissions, the rate for which dropped from 6.5% in 2013 to 1.84% in 2017, find the researchers, led by S. Cassandra Pingali, a fellow in the Immunization Services Division of the U.S. Centers for Disease Control and Prevention. Meanwhile, the slight increase in 2017 is related to the rising number of children using medical exemptions and a jump in the number of kindergarteners who are overdue for vaccinations. Senate bill 277 also allowed 5,310 kindergarteners in 2017 to forgo vaccinations s if they attended a school without classroom-based instruction or had individualized education plans.

The authors find that California communities reacted differently to the three interventions. In 2016 and 2017, reductions in the share of kindergarteners with incomplete vaccinations appear to be largest in the southern part of the state. “Northern California maintained the highest predicted rate of students without up-to-date vaccination status throughout the study period with relatively minor changes during the implementation of the 3 interventions compared with the rest of the state,” the authors write.


Elimination of Nonmedical Immunization Exemptions in California and School-Entry Vaccine Status
Delamater, Paul L.; et al. Pediatrics, June 2019.

This study looks at Senate Bill 277’s effect on the percentage of California students entering kindergarten with incomplete vaccinations. A key takeaway: While the percentage of kindergarteners whose vaccinations were not up to date fell during the first year of the law, it rose in the second year.

Researchers tracked three categories of children who had not received all school-mandated vaccinations: those who were allowed to start kindergarten as conditional entrants, students who were overdue to receive one or more vaccinations and those who were “exempt” because they either attend a school without classroom-based instruction or have individualized education plans.

The researchers find that the percentage of kindergartners starting school not up to date on their vaccinations fell from 7.15% to 4.42% during the first year after Senate Bill 277 was enacted. But much of this drop was due to a reduction in the number of children who entered kindergarten on a conditional basis, the researchers note. The conditional entrance rate fell from 4.43% to 1.91% in 2016. In the second year after the law took effect, the percentage of kindergartners who weren’t up to date on their vaccinations increased by 0.45%.

It appears that personal belief exemptions “were replaced by other mechanisms allowing kindergarteners not up-to-date on vaccinations to enter school,” writes the research team, led by Delamater.

“Some parents who would have claimed a personal belief exemption before SB277 may have initiated the series of vaccines to meet the requirements for conditional entrance after the law’s implementation,” the authors write. “Yet, data reporting progression toward series completion are not available and we are not able to know whether or when students became fully up-to-date on vaccinations.”

The authors also find that many of the parents who sent their children to school with incomplete vaccinations after Senate Bill 277 was enacted lived in the same geographical areas where many parents previously had filed personal belief exemptions. “Previous geographic patterns of vaccine refusal persisted after the law’s implementation,” the authors write.


Do Stricter Immunization Laws Improve Coverage? Evidence from the Repeal of Non-medical Exemptions for School Mandated Vaccines
Richwine, Chelsea; Dor, Avi; Moghtaderi; Ali. Working paper for the National Bureau of Economic Research, May 2019.

While other studies established a relationship between California Senate Bill 277 and higher childhood vaccination rates, this study finds that the new rule actually caused California vaccination rates to improve. This study also differs from others by examining changes in vaccination rates for each of the four vaccines required for kindergarten. The three researchers — Richwine, Avi Dor and Ali Moghtaderi of George Washington University — find that vaccination rates rose among all four vaccines in California, ranging from an increase of 2.5% for the measles, mumps and rubella (MMR) vaccine to an increase of 5% for the polio vaccine.

As part of their analysis, Richwine, Dor and Moghtaderi looked at parents’ use of personal belief exemptions and medical exemptions in California before and after Senate Bill 277 was enacted and compared it to parents’ use of these exemptions in seven control states — Arizona, California, Connecticut, Kansas, Minnesota, Pennsylvania and Rhode Island. What they learned is this: Compared to control states, California had lower vaccination rates and higher rates of students using personal belief exemptions in 2015, the year before the legislation took effect. After California banned personal belief exemptions, the rate of students using them there fell below that of the control states. However, California also “experienced a sharp increase in medical exemptions while control states’ exemption rates remained unchanged.”

Richwine, Dor and Moghtaderi find that California’s policy change reduced the rate at which children used personal belief exemptions by 3.4 percentage points. But that drop was offset by “a significant 2 percentage-point increase in medical exemptions in several of our analyses, which limits the overall decline in total exemptions to just 1 percentage-point.”


Sociodemographic Predictors of Vaccination Exemptions on the Basis of Personal Belief in California
Yang, Y. Tony; et al. American Journal of Public Health, January 2016.

This study’s main finding: White, upper-income parents were most likely to seek personal belief exemptions in California before the state banned them. The research team — led by Y. Tony Yang, currently executive director of George Washington University’s Center for Health Policy and Media Engagement — analyzed millions of kindergarteners’ vaccination data to identify where in the state personal belief exemptions were most prevalent. The team combined vaccination data from the 2007-08 to 2013-14 academic years with data from the U.S. Census Bureau’s 2008–2012 American Community Survey to better understand the characteristics of families who used these exemptions.

The researchers find that the percentage of California kindergartners who used personal belief exemptions to forgo vaccinations rose from 1.54% in 2007-08 to 3.06% in 2013-14. The share of private school students using these exemptions was almost twice as high as the share of children using them in public schools.

Yang and his colleagues also find that the “areas of California with higher household income and proportion White population are associated with higher overall PBE [personal belief exemption] percentages as well as greater increases in PBEs [personal belief exemptions].”

“An increase in percentage White population from 20% to 35% yielded 1 additional PBE [personal belief exemption] per 280 students in 2013, and an increase from 65% to 80% yielded 1 additional PBE [personal belief exemption] per 139 students,” they write.


Parent Psychology and the Decision to Delay Childhood Vaccination
Callaghan, Timothy; et al. Social Science & Medicine, July 2019.

For this study, researchers analyzed data collected through a national, online survey to better understand why some families delay childhood vaccinations. A total of 7,019 U.S. adults responded to the September 2018 survey, 31% of whom were parents with children under age 18 living at home. The parents answered a series of questions about childhood vaccinations.

Researchers find that parents with high levels of “conspiratorial thinking” and those uncomfortable with needles were more likely to say they have followed a vaccination schedule that differs from what’s recommended by the CDC. Parents with high levels of conspiratorial thinking agreed with statements such as “Even though we live in a democracy, a few people will always run things anyway” and “Much of our lives are being controlled by plots hatched in secret places.”

“Compared to those who scored lowest on conspiratorial thinking, those who scored highest were 15% more likely to report having delayed vaccinating their children, 11% more likely to have chosen their doctors based on their willingness to delay, 25% more likely to have only vaccinated their children for schools, and 18% more likely to state that they would be willing to relocate in order to attend a school that does not strictly enforce vaccination requirements,” write the authors, led by Timothy Callaghan, an assistant professor of health policy and management at Texas A&M University.

The authors also find that “individuals most sensitive to needles are between 14 and 16% more likely than those without sensitivity to display [vaccine] hesitant behavior.” The analysis also indicates “fathers are more likely than mothers to display many vaccine delay behaviors.”


Looking for more research on student vaccinations? We’ve highlighted studies that look at how often pediatricians dismiss patients for vaccine refusal and state laws that require middle school students to get a tetanus, diphtheria and pertussis (Tdap) booster vaccination.



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