Tarrant County at risk for measles outbreak as vaccination rates plummet among children

Not enough Tarrant County kindergartners are vaccinated to prevent a measles outbreak in school districts should the contagious virus be introduced locally, according to new data released by the state health department.

In the Fort Worth school district, the county’s largest, only about 86% of kindergartners had received the vaccine that protects against measles, mumps and rubella.

“Eighty-six percent is pretty darn low overall, so there is a potential for community wide outbreak,” said Catherine Troisi, an infectious disease epidemiologist with UTHealth Houston School of Public Health.

Dr. Pedro Piedra, a professor of molecular virology and microbiology at Baylor College of Medicine, the number is not enough to have significant herd effect.

The vaccination data covers the 2022-23 school year, and shows that the rates for children in North Texas have not yet recovered from the COVID-19 pandemic, which caused a significant decline in the number of children vaccinated against preventable disease like measles, chickenpox, polio, and and more. Before the COVID pandemic, in October 2019, about 95.9% of kindergartners in the Fort Worth district had received the measles, mumps, and rubella vaccination.

The pandemic disrupted access to vaccines and other preventive care for a number of reasons, said Dr. Shane Fernando, assistant professor at the Texas College of Osteopathic Medicine. Initially, kids who received vaccines or health care at their school lost access when schools closed, and their families might have lost access if they lost health insurance. When students returned to schools, Fernando added, the urgent need to get students’ caught up on lessons they had missed meant some schools relaxed their vaccination policies. And finally, misinformation about the COVID-19 vaccine and its safety has spilled over into other vaccines.

All of these forces, Fernando said, must be combated by a local and school health system that is still recovering from COVID.

To attend public schools in Texas, students are required to be vaccinated or else file a medical, conscientious, or religious exemption to receiving a vaccine.

Although the vast majority of Texans do choose to vaccinate their children against preventable disease, the number of families who opted against vaccination has jumped in the last decade. Overall, the schools with the lowest vaccination rates throughout the state were private schools and charter schools.

Countywide, about 92.4% of kindergartners had received the MMR vaccine, lower than the statewide average of 94.7%.

Vaccines provide two primary benefits, Piedra explained: First, they provide protection to the person who has received the shot, and decrease the patient’s chances of getting sick or dying from the disease in question. But the broader community benefit of vaccines, Piedra said, happens when enough people in a given community have been protected against a disease to reach a state of herd immunity. When herd immunity has been reached, a case of measles in an unvaccinated person is unlikely to travel very far, because the chain of transmission will be blocked by people who are vaccinated. Widespread vaccination helps protect infants, people who are older, and people with certain medical conditions, all of whom have compromised immune systems and are more at risk for disease, even if they’ve been vaccinated, Piedra said.

The measles vaccine is one of the most closely watched by public health experts, because measles is so transmissible and can spread rapidly among people who aren’t vaccinated. Most experts agree that at least 95% of a community need to be protected against measles to prevent outbreaks.

Because measles is not spreading within communities or throughout the U.S., virtually every known measles outbreak in recent U.S. history has happened when someone traveled abroad and brought the virus back to the country, where the traveler has transmitted the virus to susceptible, unvaccinated communities. Outbreaks typically occur when a cluster of unvaccinated people live, work, or play in the same community, and then a traveler introduces the virus to that community, said Diana Cervantes, an assistant professor at the University of North Texas Health Science Center, told the Star-Telegram in March.