Measles is highly infectious — not a benign disease — and people need to get the vaccine. That is the blunt warning from health experts as they keep an eye on what is being called a “measles epidemic” in the state of Texas specifically, due to a “growing anti-vaccination movement.”

“Measles remains a threat,” said Dr. Amesh Adalja, a board-certified infectious disease physician at the University of Pittsburgh. “Thousands die from it annually and the only means to prevent it is through vaccination. Vaccination against measles has saved countless lives and is a testament to technological and scientific process. To be against vaccination is a return to the primitive.”

Related: Measles Vaccine: Not Something to Skip

Because the virus really hasn’t been around much the past 50 years, it can be easy to get complacent and feel there is little risk in forgoing the vaccine. But prior to the measles vaccine in the early 1960s, serious epidemics occurred among school-aged children every two to three years.

Globally, measles was a leading killer among children, causing millions of deaths annually.

So infectious disease experts, such as Peter Hotez of Houston, are keeping a close eye on the Lone Star State. His new study, published in the journal PLOS, found that “there are now almost 45,000 children with nonmedical or ‘reasons of conscience’ exemptions to school immunization laws, almost double the number of exemptions in 2010 and a 19-fold increase compared to 2003.”

Related: Diseases We Thought We’d Wiped Out

And given that the measles virus is one of the most highly transmissible human infectious disease agents known — one case could generate, on average, 12 to 18 new cases, the report stated — there is concern about a large-scale measles outbreak again in the U.S.

[lz_bulleted_list title=”Measles in U.S.” source=”http://www.cdc.gov”]From January 2, 2016, to October 8, 2016, 54 people from 16 states (Alabama, Arizona, California, Colorado, Connecticut, Florida, Georgia, Hawaii, Illinois, Massachusetts, Minnesota, New York, North Carolina, Tennessee, Texas, and Utah) were reported to have measles.|In 2015, 189 people from 24 states were infected.|In 2014, there were 667 cases from 27 states.[/lz_bulleted_list]

“Vaccine coverage among a population needs to be extremely high, typically exceeding 90–95 percent, in order to prevent a measles outbreak in a school or similar setting. However, the latest numbers from Texas indicate a serious downward trend in vaccine coverage to the point where there is a high risk that measles outbreaks will return,” Hotez stated in his report.

Who do you think would win the Presidency?

By completing the poll, you agree to receive emails from LifeZette, occasional offers from our partners and that you've read and agree to our privacy policy and legal statement.

“Measles is the most contagious disease known to man, and very high vaccination rates are required to keep it at bay,” Adalja told LifeZette.

“The threat of measles in the U.S. is very real and will continue to exist until pockets of the unvaccinated are minimized. It is important to remember, based upon when the measles vaccination series is started and those with diseases that preclude vaccination, that there will always be susceptible individuals in the U.S., and the anti-vaccine movement places these individuals at risk,” he added. “The anti-vaccine movement has a real grip on the population and has damaged the public’s confidence in vaccines. It also has pushed state legislatures to craft wide exemption policies at schools.”

Related: Take Meningitis Seriously, Students

The warnings come as another new study found a deadly complication of measles in young children that strikes years after infection — and may be more common than previously thought.

The risk of acquiring the fatal neurological disorder, subacute sclerosing panencephalitis (SSPE), was believed to be about one in 1,700, based on an earlier German study of children under five years of age infected with measles. The new research looked at children who got measles during a large California outbreak around 1990. It found the rate of SSPE to be one in 1,387 for those infected before the age of five. It rose to about one in 600 for babies infected before their first birthday.

[lz_ndn video=31327627]

Researchers hope the data will bring awareness to parents who refuse vaccines for their children. They also caution parents not to travel with unprotected children to countries where measles is endemic, such as the Philippines, as it is “too risky.”