A rise in Austin-area vaccine exemptions worries some health officials

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]…