Photograph By Joe Amon / The Denver Post via Getty

Even in an era defined by profound technological advances, the practice of medicine remains an art as well a science—a fact that often frustrates both physicians and their patients. For many conditions, solutions are not simple and there are rarely easy answers. There are exceptions, of course; perhaps the most notable among them has been the success of vaccines.

Until recently, in the United States and other wealthy countries, diseases such as measles, pertussis and rotavirus—which kill hundreds of thousands of infants in the developing world each year—had virtually disappeared. Both measles and pertussis are now back, largely because increasing numbers of children remain unvaccinated. Vaccines are the most powerful public-health tool that pediatricians possess. Unfortunately, there are people (a minority, but a dangerous one) who just don’t care.

Many of these people don’t approve of the vaccine schedule set out by the Centers for Disease Control and Prevention, and they seek to spread the shots over a longer time period than the one recommended. This has presented American pediatricians with a stark new challenge to their Hippocratic Oaths. Which does more harm: delaying scheduled vaccines and reducing their effectiveness, or refusing to delay and running the risk that parents will simply not vaccinate their children at all?

It’s a terrible choice, forced almost wholly by the notion (which is demonstrably untrue) that if a child receives “too many vaccines too soon” it could overwhelm his or her immune system. A study published this week in the journal Pediatrics provides the best proof yet that a large majority of doctors agree to the delays. Ninety-three per cent of those surveyed for the study reported that they had been asked, at least once, to delay vaccines. The physicians acquiesce in overwhelming numbers—two thirds said they do so at least occasionally—even though most of them don’t want to, and even though they are aware that data clearly show that such delays put their patients (and those around them) at increased risk.

Nobody can dispute that the number of vaccines has grown significantly. A hundred years ago, children received a single vaccine: smallpox. By 1962, that number had grown to five (diphtheria, pertussis, tetanus, polio, and the M.M.R.). Today, the C.D.C. advises that children be vaccinated for fourteen diseases before age six, on a recommended schedule that usually includes twenty-nine shots, sometimes several at once. Vaccines worry parents, in part because of an old, unfounded, and ultimately discredited theory that children who receive measles vaccines develop autism at higher rates than other children. (They don’t, as has been demonstrated in dozens of studies carried out throughout the world.)

That baseless concern, publicized by activists such as Jenny McCarthy, morphed into a movement to spread out the timing of vaccines in order to protect children from a possible shock to their immune systems. But there simply is no such threat. Because progress in molecular biology has made it possible to create vaccines with fewer antigens, children’s systems are now exposed to far less of a burden than was the case in the past. The smallpox vaccine, for example, contained two hundred proteins—all separate molecules. All together, the vaccines that children routinely receive today contain fewer than a hundred and fifty.

The number of bacteria that live on the nose of a newborn child or on the surface of his or her throat is in the trillions. “Those bacteria have between 2,000 and 6,000 immunological components and consequently our body makes grams of antibody to combat these bacteria,” Paul Offit, the chief of the infectious-diseases division at the Children's Hospital of Philadelphia, has written. “The number of immunological challenges contained in vaccines is not ﬁguratively, it is literally a drop in the ocean of what you encounter every day.” Offit has long been one of the nation’s most prominent proponents of vaccines—and he has long been vilified for his stance.

Pediatricians spend, on average, less than twenty minutes with each patient—often _far _less—and they usually have to cover a lot of ground. Finding the time for a lengthy discussion of vaccine safety is never easy. Moreover, at least one recent study suggests that certain efforts to correct false impressions about the dangers of vaccines actually make people less likely to get vaccinated. It appears, again for no good scientific reason, that simply knowing more about vaccines convinces many people to avoid them.

The days when patients stood by placidly as doctors told them what to do are over, and good riddance to them. We are far more capable of assembling information and deciding what is best for us or for our children than we ever have been. And we certainly have the energy to devote to our fear of disease. (Anyone who watched as the nation displayed hysteria over “our” Ebola epidemic, in which two people in a nation of three hundred and thirty million died, saw that.)

But the medical profession’s widespread surrender on vaccines is deeply troubling. And it all but guarantees that preventable illnesses will continue to harm people and put children’s lives in danger. An Internet connection doesn’t make us all experts, and it doesn’t make it easier to distinguish between useful data and lies. That’s why trained physicians and nurses are more essential today than they have ever been. Unfortunately, that is not a truth universally acknowledged—even by doctors.