As of mid-May, health experts at the U.S. Centers for Disease Control and Prevention had tallied more than 1,000 cases of measles in the U.S. this year, including a handful in Colorado. Three people with measles, including two young children, have died in Texas, where the current outbreak started.

Those three deaths among roughly 1,000 cases showed an unlucky affinity to the statistics compiled before the measles vaccine’s approval back in 1963. Before then, nearly 4 million people a year contracted this highly contagious virus each year in the United States alone, with 1 in 20 ending up with pneumonia, one in 1,000 having brain swelling that could cause deafness and intellectual disability, and, yes, three in 1,000 dying. About 48,000 were hospitalized each year, despite a population just over half of today’s.

In 1971, the U.S. Food and Drug Administration approved the first combined measles, mumps, rubella (MMR) vaccine. Its mass rollout dramatically reduced the number of U.S. measles cases by more than 99%. By 2000, measles had been eradicated in the United States.

But measles is back — despite U.S. MMR vaccination rates above 90% (schools generally require it). The issue is that the extreme transmissibility of measles (nine in 10 of those unvaccinated will contract it when exposed) means that 95% of the population must be immunized to achieve herd immunity. Colorado’s current MMR vaccination rate stands at 93.7%. Why it’s not higher rests largely at the feet of a fraudulent and discredited 1998 British study of a dozen cherry-picked cases.

Subsequent studies from around the world involving hundreds of thousands of subjects all have come to the same conclusion: MMR vaccines do not cause autism. In fact, a major Danish study found

“We’ve got a half-century of data on this. There’s no connection,” said Ross Kedl, who has a doctorate and is an immunologist and vaccinologist at the University of Colorado School of Medicine on the Anschutz Medical Campus.

Vaccine safety is serious business

Don’t take his word for it, Kedl says. The studies are out there on PubMed and elsewhere.

“Nobody’s hiding data. Nobody’s being secretive. Nobody’s stashing away hidden studies,” Kedl says. “If scientists have an answer, for God’s sakes, we want the world to know. So we publish everything, because our reputations are based on that.”

In other words, if vaccines really did cause autism, scientists such as Kedl would get the word out. Researchers have kids, too, after all.

What’s more, ongoing vaccine safety is closely monitored through the U.S. Department of Health and Human Services’ Vaccine Adverse Event Reporting System (VAERS) and the Centers for Disease Control and Prevention’s Vaccine Safety Datalink (VSD). Potential safety signals are also monitored by each manufacturer.

For example, Kedl says, U.S. and European monitoring helped officials quickly spot rare cases of blood clotting from the adenovirus-based Johnson & Johnson COVID-19 vaccine, which ultimately led to its pause and phase-out. That’s despite the problem having occurred, on average, fewer than four times per million doses.

“Based on a handful of cases across millions and millions of doses given within a couple of weeks, they figured it out because of those safety-monitoring systems,” Kedl said.

The moral burden of misinformation

Kedl and colleagues share frustration with how the messaging coming from some of the nation’s top health officials fuels vaccine skepticism.

Notions that the measles component of the MMR vaccine wears off quickly are false. Its protection is durable over decades.

Placebo-controlled trials have been a vaccine-development mainstay. But when it comes to proven vaccines (such as, say, flu or coronavirus vaccines) that require subtle changes to keep up with fast-mutating viruses, running new placebo-controlled trials risks slowing down rollout until the viruses have mutated yet again.

If home remedies such as cod liver oil (or the vitamin A it contains) protected against measles, why did infection rates only plunge after the measles vaccine’s rollout? And neither cod liver oil, nor aerosolized budesonide, nor the antibiotic clarithromycin work as first-line measles treatments. In fact, there are no first-line measles treatments, and viruses skirt antibiotics anyway.

Also surprising to Kedl is the questioning of the safety and effectiveness of MMR and other vaccines that have been exhaustively studied and given to billions of people with scant side effects and enormous public health benefits.

He says he and colleagues have come to conclude that the opposite of gullibility isn’t intelligence. Many who fall under the spell of dubious vaccine-related ideas are plenty smart. Rather, it’s curiosity, or a lack of it, that degrades the otherwise wise refrain of “do your own research” into an effort either skipped entirely or blighted by skewed sourcing.

If expertise didn’t matter, you wouldn’t need a dentist

Certainly, bad science exists – that retracted 1998 Lancet report being a case in point. But to ignore the conclusions of so many rigorous, peer-reviewed studies done by specialized experts over many years is fraught, Kedl says. He likens it to disregarding your dentist’s call for a crown or consulting an electrician on the state of your teeth, which is what you’re doing when relying on the word of pundits over the work of experts.

“I go to a dentist for my teeth, not an electrician, and I don’t usually question my dentist,” Kedl said.

Ultimately, moving on from the false connection between MMR vaccines and autism is a moral imperative, Kedl says. The roots of autism are complex and poorly understood. Misplaced attention on the MMR vaccine distracts from the crucial work of identifying and addressing the true causes of the disorder.

“Autism rates have risen, and the longer we circle back to test out what we already know, the longer it will take to get to the real answer,” he said.