Five years ago, Austin Regional Clinic pediatricians first became aware of the increasing prevalence of children coming into its clinics without being vaccinated.

Out of a concern for the safety of other children who had not yet been immunized and immunocompromised patients, ARC began crafting a new policy.

“At that same time we were hearing more about outbreaks of measles, mumps—polio, even—generally tied to the unvaccinated populations,” ARC’s Chief of Pediatrics Dr. Alison Ziari said. “We felt like it was becoming more of an issue, and we needed to do something.”

In 2015, ARC announced it would no longer accept new pediatric patients who are not vaccinated. ARC’s physicians brought up the new policy at a child’s next visit and answered parents’ questions about vaccines. Out of ARC’s 60,000 pediatric patients, the clinic only discharged 200 patients whose parents decided not to immunize their children, Ziari said.

ARC’s stance had a ripple effect in the community,  Ziari said, because many area clinics adopted similar policies. Nearly every pediatric practice Community Impact Newspaper contacted requires children to be immunized. Only two area pediatrician’s offices said they do accept children who have not been immunized, but the physicians could not be reached for interviews.

Maintaining herd immunity

Vaccinations work by imitating a disease and strengthening the body’s own immune system to fight against contagious diseases, such as the measles or mumps, according to the Centers for Disease Control and Prevention.

Some people cannot be vaccinated because their immune systems are compromised or they are not old enough to be vaccinated. Herd immunity can provide protection to those who are not immunized when enough of the population is vaccinated, said Dr. Phil Huang, medical director for Austin Public Health.

“Infants and older people are sometimes the most susceptible to these illnesses we’re providing vaccines for,” he said.

According to a widely cited 1993 study published by The Johns Hopkins University School of Hygiene and Public Health, each disease has a different vaccination threshold based on how contagious it is. For example, measles is very contagious, and between 85 percent and 94 percent of the population must be vaccinated to provide herd immunity, according to the study.

As exemption rates rise, some local health officials are becoming worried about losing that herd immunity, especially where there are clusters of people who are not vaccinated, Ziari said.

“In our community we have so much international travel, people coming in and out all the time. That was our worry,” she said. “... When you see [vaccine exemptions] rising, then that means your herd immunity’s going down and then we’re going to see an outbreak.”

A 2014 outbreak of measles at Disneyland in California led the state to ban personal and religious exemptions for vaccines in 2015.

Huang said the number of vaccination exemptions statewide has risen from about 3,000 in 2003, when the conscientious exemption law became effective, to more than 45,000 in 2015. To ensure the safety of the public from the spread of contagious diseases, he said public officials focus on the safety and effectiveness of vaccines.

“If we’re doing our job, you don’t hear about us, you don’t think about us because it’s quiet,” he said. “It’s when something goes wrong, when something isn’t being done, that then there’s this potential for outbreaks.”

Rising exemption rates

ARC implemented its new policy in part because of the increasing number of students at area school districts who are not immunized. In Austin ISD, the number of students with a conscientious exemption rose from 0.59 percent in the 2005-06 school year to 2.17 percent in 2016-17. Round Rock ISD had a higher percentage of exempted students at 2.31 percent for the 2016-17 school year, according to state data.

But Dawn Richardson, co-founder of Parents Requesting Open Vaccine Education, which helped push for the statewide conscientious exemption approved in 2003, said the vaccine-tracking system violates rights of privacy and is misleading.

“A vaccine exemption is required to be filed if the kid is missing one dose of one vaccine [or] all doses of all vaccines,” she said. “A kid could be just not getting the chickenpox vaccine but get everything else.”

Richardson said the individual vaccine coverage rates show that more children are being vaccinated.

“All the vaccine rates stay about the same or go up for every individual vaccine,” she said. “What does the exemption rate matter if the vaccine rates are going up?”

Data from the Texas Department of Health and Human Services shows vaccination rates for individual vaccines have remained relatively high among kindergartners. For the 2006-07 school year, the number of kindergartners in Texas who had the diphtheria, tetanus and pertussis vaccine was 97.7 percent compared to 97.2 percent in the
2016-17 school year.

Understanding information

Ziari said reasons parents choose not to immunize their children run the gamut.

“Some people have philosophical or political reasons; those tend to be the ones we just had to part ways [with]  and respectfully so. That’s OK. But a lot of times it’s parents being confused,” she said. “There’s just so much information.”

ARC directs patients to reliable sources, such as the CDC, Baylor College of Medicine and Texas Children’s Hospital, for additional information on vaccines.

Dr. Stephen Pont, whose roles include being a pediatrician at Dell Children’s Medical Center, a spokesperson for the American Academy of Pediatrics and medical director at Austin ISD Student Health Services, said AISD and the AAP also aim to be a trusted source of information.

“If there are families who are really concerned, we want them to know we are here to have those conversations with them,” he said. “Oftentimes having those conversations alleviates anxiety, and families come to understand and feel secure with it, that these are safe for those kids to get.”

Richardson said many vaccine-choice parents tend to favor private schools where they are around other like-minded parents.

“Private schools will have higher rates of exemptions because ... public schools are not upfront about the vaccine exemption process,” she said. “You will have a congregation of [exemptions] in a particular area. It has been like that since the vaccine requirement laws have gone into effect, and there really hasn’t been a history of that ever really causing a problem.”

She said informed consent is the cornerstone of medicine in that people are given information, including benefits and risks, and left to make their own decisions about their health care.

“You are in partnership with your doctor to make those decisions,” she said. “Vaccines are pharmaceutical projects that carry a risk of injury and death. All diseases are not the same, and all children are not the same.”

Olivia Lueckemeyer contributed reporting to this story.