In the march of progress, there inevitably comes resistance. Even as success is rewarded, fear still finds traction.

Such is the history of vaccination. In the 64 years since Jonas Salk’s stunning invention of a polio vaccine — a development that made a once prevalent disease all but forgotten — literally millions of lives have been saved and untold misery avoided by vaccines.

Chalk up another victory for institutional mistrust. An environment that allows bad information to travel in its own dark circles is the perfect vehicle for health conspiracies. In particular, misplaced concerns over vaccines causing autism continue to depress immunization rates — despite a lack of evidence that vaccine-caused autism has ever happened.

All Utah parents are required to either prove their children are vaccinated or sign a form that says they personally object to vaccination. That’s true at charters and traditional schools. But the rates of those who object are higher at charter schools. As a result, their infection rates are higher, too.

Do the charters do anything to discourage vaccination? Not likely. It’s more a matter of self-selection. Those parents attracted to alternative education theories may also be attracted to alternative health theories.

Ultimately, those who choose not to vaccinate their children are just bad gamblers.

Everything has risk. There are indeed adverse reactions to vaccines for a small number of people, reactions that could be avoided if they didn’t get vaccinated.

But in any kind of honest look at the risk, not vaccinating carries much more potential for harm. And that harm doesn’t end with the children who aren’t vaccinated. Even if they never become ill, they can be carriers who spread the virus. That is why most states don’t allow as many vaccination exemptions as Utah does. It’s a personal decision that affects a larger group.

In the case of chickenpox, vaccination is an imperfect game. The vaccine is not 100 percent effective. In fact, recent data shows 69 percent of Utah schoolchildren contracting chickenpox were vaccinated against it. Still, a vaccine can nearly eradicate a disease if the maximum number of people get vaccinated. It’s called herd immunity. If enough of a group is immunized, exposure to the virus may cause some illness, but it won’t cause an outbreak.

Utah should tighten its exemption rules to keep its children and adults safer. Vaccination is arguably the greatest achievement of the 20th century. It shouldn’t be undone by the dubious suspicions of the 21st.