HOUSTON (CN) – A new study warns that Dallas and Austin are fertile ground for large measles outbreaks that could spread to other Texas cities due to the growing number of parents getting vaccine exemptions for their children.
Drawing on U.S. Census data and vaccination data from Texas public and private schools, University of Pittsburgh researchers used a computer program to simulate people’s movements in their cities from home to work or school, to illustrate how measles infections could spread.
The simulator introduced one randomly selected child “whose parents have refused to vaccinate” into various Texas metropolitan areas and ran for 270 days—the length of a typical school year—in all the cities.
“At current rates, the simulation estimates that measles outbreaks of more than 400 cases could occur in Austin and Dallas-Fort Worth. This is partly due to a minority of schools where vaccination rates are less than 92% — low enough for measles to sustain transmission,” the University of Pittsburgh Graduate School of Public Health team said in a statement about their study, published Wednesday in the journal JAMA Network Open.
See a video simulating the spread of an outbreak in Austin here.
Experts say at least 93% of the population must be immunized against measles to achieve the so-called “herd immunity” threshold and prevent large outbreaks.
The study’s authors say, “If the vaccination rate drops 5% in only the schools with populations that currently are undervaccinated, the size of potential measles outbreaks climbs exponentially in every metropolitan area, with Dallas-Fort Worth, Austin and Houston all susceptible to outbreaks of 500 to 1,000 people.”
The virus makes its home in the nose and throat of infected people. If they cough or sneeze, it can linger in the air for up to two hours and 90% of non-immunized people who enter that space will get infected, according to the Texas Department of State Health Services.
One to three weeks after exposure, the victim might think they just have a cold as they will develop a mild fever, cough, runny nose, red eyes and sore throat. But the telltale sign—a red rash—will break out and spread from their face down, covering their entire body.
The University of Pittsburgh researchers, who did the study at the request of the Texas Pediatric Society, said measles can cause pneumonia, brain swelling and deafness.
“Approximately 1 out of every 1,000 children infected with measles will die from respiratory and neurologic complications,” they said in a statement.
But a belief that vaccinations cause autism has fueled a large “anti-vaxxer” movement in Texas, led by Austin resident and former British doctor Andrew Wakefield.
The U of Pitt team says the number of Texas children whose parents have opted out of them receiving vaccinations for religious or personal reasons increased from 2,300 in 2013 to 64,000 in 2016.
With more than 28 million residents, Texas is the most populous state that let parents obtain such exemptions, the study authors say.
Wakefield moved to the U.S. after the British General Medical Council barred him from practicing in the United Kingdom in 2010. The council found he had abused the trust of disabled children for his research suggesting a link between autism and the measles, mumps and rubella (MMR) vaccine.
Wakefield directed the documentary “Vaxxed: From Cover-Up to Catastrophe.” According to the film, released in 2016, the Centers for Disease Control and Prevention silenced a staff epidemiologist who disclosed the agency had thrown away data from a CDC study linking autism to MMR shots.
As of July 30, 21 people in Texas have been infected with measles in 2019, up from just one measles case reported in 2017, according to the Texas Department of State Health Services.
The Texas cases are 1.7% of the 1,203 confirmed infections in 30 states through Aug. 15, according to the CDC. “This is the greatest number of cases reported in the U.S. since 1992 and since measles was declared eliminated in 2000,” the CDC said in a recent report.
The CDC says more than 75% of the 2019 cases arose from outbreaks in New York and New York City, with a cluster of infections occurring among children in Orthodox Jewish communities.
New York state legislators moved quickly in response, passing a law in June nixing religious exemptions for schoolchildren.
After signing the bill Governor Andrew Cuomo said, “I understand freedom of religion. I have heard the anti-vaxxers’ theory, but I believe both are overwhelmed by the public health risk.”