It's looking as if 2017 could become the year when the anti-vaccination movement gains ascendancy in the United States and we begin to see a reversal of several decades in steady public health gains. The first blow will be measles outbreaks in America.

Measles is one of the most contagious and most lethal of all human diseases. A single person infected with the virus can infect more than a dozen unvaccinated people, typically infants too young to have received their first measles shots. Such high levels of transmissibility mean that when the percentage of children in a community who have received the measles vaccine falls below the range of 90 percent to 95 percent, we can start to see major outbreaks, as in the 1950s when, on average, 4 million Americans a year were infected and 450 died. Worldwide, measles still kills around 100,000 children each year.

The myth that vaccines like the one that prevents measles are connected to autism has persisted despite rock-solid proof to the contrary. Donald Trump has given credence to such views in tweets and during a Republican debate, but as president he has said nothing to support vaccination opponents, so there is reason to hope that his views are changing.

However, a leading proponent of the link between vaccines and autism said he recently met with the president to discuss the creation of a presidential commission to investigate vaccine safety. Such a commission would be a throwback to the 2000s, when Rep. Dan Burton of Indiana held fruitless hearings and conducted investigations on this topic. And a documentary alleging a conspiracy at the Centers for Disease Control and Prevention, Vaxxed: From Cover-Up to Catastrophe, has recently been shown around the country.

As a scientist leading global efforts to develop vaccines for neglected poverty-related diseases like schistosomiasis and Chagas disease, and as the dad of an adult daughter with autism and other disabilities, I'm worried that our nation's health will soon be threatened because we have not stood up to the pseudoscience and fake conspiracy claims of this movement.

Texas, where I live and work, may be the first state to once again experience serious measles outbreaks. As of last fall, more than 45,000 children here had received nonmedical exemptions for their school vaccinations. A political action committee is raising money to protect this "conscientious exemption" loophole and to instruct parents on how to file for it. As a result, some public school systems in the state are coming dangerously close to the threshold when measles outbreaks can be expected, and a third of students at some private schools are unvaccinated.

The American Academy of Pediatrics has produced a 21-page document listing all of the studies clearly showing there is no link between vaccines and autism, in addition to more recent epidemiological studies involving hundreds of thousands of children or pregnant women that also refute any association. A study of infant rhesus monkeys also shows that vaccination does not produce neurobiological changes in the brain.

Vaccines are clearly not the reason children develop autism. So what is? There is strong evidence that genetics play a role, and that defects in the brain of children on the autism spectrum occur during pregnancy. Exposure during early pregnancy to particular chemicals in the environment or infections could be involved. Researchers have suggested that damage could be done by the drugs thalidomide, misoprostol and valproic acid; by exposure to the insecticide chlorpyrifos; and by infection of the mother with the rubella virus.

This is what we need to be focusing on, not the myth that vaccines cause autism. Yet I fear that such myths will be used to justify new rounds of hearings or unwarranted investigations of federal agencies, including the CDC. This would only distract attention from these agencies' crucial work, and the real needs of families with children on the autism spectrum, such as mental health services, work-entry programs for adults and support for the research being done by the National Institutes of Health.

Today, parents in Texas have to live in fear that something as simple as a trip to the mall or the library could expose their babies to measles and that a broader outbreak could occur. Perpetuating phony theories about vaccines and autism isn't going to help them -- and it's not going to help children on the autism spectrum, either.

Peter J. Hotez, a pediatrician at Baylor College of Medicine, is director of the Texas Children's Hospital Center for Vaccine Development. This column was first published in The New York Times.