Billboards claiming that vaccines can “kill” children have been popping up on roadsides across the nation, prompting concerns among physicians that families are getting unproven and potentially life-threatening health information.

Several such billboards, part of a nationwide campaign by anti-vaccination group Learn The Risk, have appeared in West Virginia in recent days, the Herald-Dispatch reported. The posters suggest the young son of Nick Catone, a former Ultimate Fighting Championship fighter, died in 2017 from a vaccine.

“As a nurse, I was never taught vaccines can kill until my son was a victim,” a quote on the billboards read ― an apparent reference to Catone’s wife, a registered nurse.

BIG NEWS: FIVE BILLBOARDS GO UP HONORING NICHOLAS CATONE



Nothing will ever bring Nicholas back, but we can make sure he didn't die in vain. Nicholas will save lives. He's a true hero.https://t.co/o57tIUDpoH #LearnTheRisk #FlyHighNicholas #vaccineVICTIM #SIDs pic.twitter.com/LNXzVEEBuD — Learn The Risk (@learntherisk) September 25, 2018

The cause of the boy’s death was officially ruled sudden infant death syndrome (SIDS), but Catone has maintained that a diptheria, tetanus and acellular pertussis (DTaP) vaccine, given three weeks before the child’s death, had killed his son.

Catone partnered with Learn The Risk, a California-based nonprofit, to share what he has described as the dangers of vaccinating kids. His son would “never have gotten any” vaccines if he’d known about these alleged hazards, Catone wrote on Facebook in June. His post was shared more than 13,000 times.

According to the Herald-Dispatch, at least 30 Learn The Risk billboards linking Catone’s son’s death to vaccines have been put up in New York, Pennsylvania, Missouri and other states this year.

“It’s important to me that parents have the right information to make an informed choice about vaccines,” Brandy Vaughan, Learn The Risk’s executive director, told the Dispatch. “It’s been my mission to tell what the pharmaceutical companies are hiding.”

The Centers for Disease Control and Prevention describes DTaP as a “very safe and effective” vaccine suitable for children, including infants. The vaccine protects people against diphtheria, which can cause paralysis, heart disease and death; tetanus, which leads to death in 1 in 10 cases; and pertussis, or whooping cough, which is a highly contagious infection that can have serious complications, particularly in young children, the CDC said.

According to the World Health Organization, anti-vaccine advocates have long propagated a myth that the DTaP vaccine causes SIDS. But research shows this claim to be unfounded.

One myth that won’t seem to go away is that DTP vaccine causes sudden infant death syndrome. This belief came about because a moderate proportion of children who die of SIDS have recently been vaccinated with DTP ... This logic is faulty however. ... If you consider that most SIDS deaths occur during the age range when three shots of DTP are given, you would expect DTP shots to precede a fair number of SIDS deaths simply by chance. In fact, when a number of well-controlled studies were conducted during the 1980s, the investigators found, nearly unanimously, that the number of SIDS deaths temporally associated with DTP vaccination was within the range expected to occur by chance. In other words, the SIDS deaths would have occurred even if no vaccinations had been given.

Vaccines, like most other medical interventions, are not 100 percent effective and can cause side effects which can, in rare cases, be serious. There is overwhelming consensus among the medical community, however, that the benefits of vaccination far outweigh the risks.

In America, “millions of vaccines are given daily,” Tiffany Wilkinson, director of the Kansas City Health Department’s division of communicable disease prevention, told the Kansas City Star last month after a Learn The Risk billboard featuring Catone’s son appeared in the area. “These vaccines have been very, very important throughout our history to reduce the spread of potentially dangerous diseases. The small and rare risks associated with vaccines are outweighed by the enormity of the diseases we’re preventing by providing these vaccines to children.”

But as the Star noted, anti-vaccine sentiment has been burgeoning in the U.S., Europe and elsewhere, fueling a rise in preventable diseases.

In Europe, there have been 41,000 measles cases and at least 40 related deaths this year. Experts say a primary cause of the outbreaks has been the choice of many parents to not vaccinate their kids.

“It’s the main factor leading to the outbreaks,” a spokeswoman for the European Commission told NBC News earlier this month. “It’s unacceptable to have in the 21st-century diseases that should have been and could have been eradicated.”

The WHO says at least 95 percent of a population must have received the measles vaccine to prevent outbreaks of the disease. But according to NBC, some parts of Europe have vaccination rates of below 70 percent.

In the U.S., most states fall short of the 95 percent target. In West Virginia, for example, where the anti-vaccination billboards have recently cropped up, the rate of measles vaccination is just shy of 90 percent, according to NBC, citing CDC data.

U.S. health officials said in August that 107 people, most of whom had been unvaccinated, had contracted measles in 21 states and the District of Columbia since January. This year’s outbreak was on pace to surpass 2017′s when 118 people contracted the disease, officials said at the time.

A raging measles outbreak in Europe may be a warning sign of what could occur in the U.S. if something doesn’t change soon, experts say. https://t.co/1pZVoDUSY3 — NBC News (@NBCNews) October 22, 2018

Physicians have warned that rising numbers of unvaccinated children in the U.S. could lead to a disease outbreak with far more widespread impacts.

“This is an accident waiting to happen,” Dr. Albert Wu, a professor of health policy and management at the Johns Hopkins Bloomberg School of Public Health, told NBC News, adding that a major outbreak may be the only thing that could show anti-vaccine advocates what’s at stake.

“I’m afraid it will take a really big outbreak in the United States before we begin to see a reversal of this anti-vaccine sentiment,” Wu said.