Creutzfeldt-Jakob disease takes years to develop. Patients exposed to the infection feel fine for years but then they become moodier and forgetful and over the course of months subtle cognitive defects progress to severe dementia. Patients with CJD forget the names and faces of loved ones, they lose the ability to walk, speak, or swallow, and they lapse into a coma that has proven fatal one hundred percent of the time.

To avoid neurosurgical prion transmission, the instruments used in a patient suspected to have CJD should be destroyed or specially decontaminated. With such measures in practice, it has been thirty years since a case of CJD was attributed to contaminated surgical instruments. At Catholic Medical Center in Manchester, New Hampshire, though, the instruments used to biopsy the patient later diagnosed with CJD were sterilized via standard techniques and put back into use.

When Creutzfeldt-Jakob disease contamination of surgical instruments is discovered, doctors at Catholic Medical Center and other hospitals wonder if it is right to tell patients. In most cases the disease will never occur and there is no effective means of prevention. Even for the unlucky patients who do develop the disease – if any of them do – there is no effective therapy so advance warning gives no extra measure of hope. Worse still, there is no diagnostic test to predict who will escape infection or die, so the only thing patients can do once notified is wait. That means the only real world impact of disclosure, regardless of the eventual outcome, is patient distress. So in this case is knowledge power, or is knowledge just knowledge?

Beyond the desire not to worry patients unnecessarily, Catholic Medical Center doctors were likely tempted to hide the error in sterilization technique. Yet doctors value transparency and trusting relationships with patients, and most patients want to be notified if physicians make an error or discover an abnormal finding incidentally.

Like the 98 patients at Emory, eight patients at Catholic Medical Center in New Hampshire who were exposed to Creutzfeldt-Jakob disease were notified last week, and counseled that they will have to wait years to find out if they contracted the infection. At Cape Cod Hospital in Massachusetts and the West Haven Veterans Affairs Hospital in Connecticut, which rented the same neurosurgical instruments from Catholic Medical Center, seven additional patients will join in the wait. Fortunately, whether or not patient notification was a good idea, surveys show that patients do not suffer serious long-term distress after learning they were exposed to surgical instruments contaminated by prions. Few of us can maintain a state of high alert for very long in response to a risk that is both minuscule and abstract.

Dean Foster and colleagues at the University of Pennsylvania devised a free online calculator that estimates life expectancy based on demographics, habits and family history. Punch in the facts and out pops an estimate. Not surprisingly, smokers and drinkers are predicted to live shorter lives, whereas people in low stress jobs who get a lot of exercise live longer. Or at least that is what the calculator says. But no online calculator can predict lightning, terrorists, and other random calamities. None asks, after assessing alcohol consumption and seat belt use, “Do you expect to be notified your neurosurgical procedure was contaminated by a rare prion disease?” That means that by their calculation, beyond eating our broccoli and squeezing in a run from time to time, we really cannot know the day of our demise.

The question then is whether there is something, anything, to be gained from knowing that somewhere deep in the brain a rampaging misshapen protein with an appetite for global domination is quietly, mercilessly, taking apart the very substance of who you are. Or not. Personally I would rather live without that kind of shadow hanging over me.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.