In late January, clinical immunologist Richard Burt and his Northwestern University colleagues published the results of a study which found that stem cell transplantation could possibly halt disease progression and “reverse” neurological deficits in patients with multiple sclerosis. MS, which affects 2.5 million people worldwide, is a degenerative autoimmune disease, causing symptoms that range from loss of vision to loss of mobility. Scientists have yet to find a cure, but many hope that stem cell research may hold the answer. So when Burt’s results appeared in Lancet Neurology at the end of January (and in the print edition in March), media across the globe jumped on the story.

Unfortunately, much of the ensuing coverage failed to recognize some conspicuous red flags that should have signaled the need to proceed with utmost caution. First and foremost, the study was very small—just twenty-one patients—and there was no control (or comparison) group for the research. Burt and his colleagues explained these limitations in their study, explicitly stating that the “results need to be confirmed in a randomized trial.” And if that wasn’t enough to inspire moderation, the National MS Society patently warned that “there is no proof yet [stem cell transplantation therapy] can cure a person with MS.” Few reporters included either one of these disclaimers, however. At best, they casually mentioned or quoted Burt saying more studies are needed and underway—usually as the last line of the story.

Some of the most imprudent articles came from Bloomberg, Reuters, and the Daily Mail in London. None of these pieces included any meaningful hedge against the impression that stem cell therapy can (definitively) help people with MS. Bloomberg was the most negligent, tossing off sentences stating that the treatment “reversed” MS itself rather the symptoms or damage it causes. A more accurate description is that treatment appeared to halt progression of the disease and reversed some neurological disabilities associated with it.

The marginally better coverage of Burt’s study—from outlets such as The New Scientist, the BBC, and the Los Angeles Times—at least used mitigating language such as “appears to,” “may have,” and “promising” to express how preliminary the results were. The New Scientist, especially, deserves credit for mentioning at the top of its story that the research was very limited and needs to be replicated in larger, randomized trials.

(To be fair, most articles acknowledged that a larger study has just begun, with patients from the U.S., Canada, and Brazil, but the details of that research were lacking or unclear. The number of patients involved, for example, ranged from fifty-five in the Bloomberg story to 110 in The Times of London.)

Part of the problem for reporters, no doubt, has to do with Burt’s use of the ambiguous term “reversed.” With MS, a disease whose relapses are notoriously unpredictable and varied among individual patients, how is “reversed” defined? “Not easily” is the answer. Even Burt is not very clear on this point, telling the BBC that stem-cell therapy is not a cure, but instead something that’s “changing the natural history of the disease.” With such an opaque answer, it is no wonder that many reporters had difficulty explaining the upshot of Burt’s research.

Julie Chen of CBS’s The Early Show exemplified this confusion when she asked one of the study’s participants, twenty-four-year-old Edwin McClure: “And what do doctors tell you have to do from here? Like, when can they declare you cured?”

McClure took a deep breath and looked nervously at his mother, Bernice, who was with him for the interview. She answered, “That’s a good question. We’re not sure about that… But in our mind it’s a blessing and it’s our miracle. So in our mind he’s cured.”

Which is wonderful, but with such questioning CBS may have given false hope to others, especially when the segment was overlaid by captions such as: “Exclusive: Breakthrough for MS? Inside Groundbreaking Treatment for Patients.” (Emphasis mine.)

Burt’s research tested individuals in the early stages of relapsing-remitting MS. Scientists removed stem cells from the patient’s blood or bone marrow, used chemotherapy to destroy his or her immune system, and then infused the stored stem cells back into the person in an attempt to “reboot” the system. The hope was that the new immune cells would break the MS cycle and no longer attack the central nervous system. After thirty-seven months, all of Burt’s patients were free from progression (their disease had not grown worse) and sixteen were free of relapses (recurring symptoms). Furthermore— getting to the point about “reversal”—nearly 81 percent saw at least a one-point improvement on the Kurtzke expanded disability status scale.

One article that got all of this right and accurately characterized the significance of Burt’s research was a piece published online at Nature News. Not only did the reporter, Monya Baker, use cautionary terms like “preliminary study” and “new trial,” she sought outside opinion by interviewing the vice president for biomedical research at the National MS Society in New York, who cautioned that “Although they are impressive results, it’s a preliminary study,” and the director of another MS research center at the University of Maryland who stressed how promising the results were, but cautioned that larger studies were needed.

Furthermore, Baker did something that all others failed to do. She questioned the treatment’s expected fatality risk—which, according to Burt, is roughly 1 percent—by comparing it with the withdrawn MS drug Tysabri, which has a 1 in 1000 chance of causing a serious viral infection. “Those risks were considered so serious that [Tysabri] was initially withdrawn from sale by the manufacturer,” the article stated. “It is now only prescribed under a special prescription programme in the United States and carries serious warnings in Europe.” To support this point, Bayer quoted a commentary by an Italian researcher published in the same edition of Lancet Neurology as Burt’s study, which argued that “Burt’s therapy cannot be considered gentle, because there are certainly side effects of some importance.”

Indeed, the limitations of Burt’s study were such that some journalists didn’t bother. Robert Bazell, NBC News’s chief science and health correspondent, said he decided not to cover the results after reading the press release and journal article. “The reason was the relatively small number of patients and the author’s upfront acknowledgement of the need for a controlled study to prove the outcome,” he wrote in an e-mail. “In its favor, I know these scientists and respect them, but I believe this study falls into the category of a report that should be encouraging others to continue the work … as a TV presentation [it] would do nothing but offer false hope.”

Still, Bazell does not fault other journalists for covering Burt’s research, noting, “There are no hard and fast rules we follow about these things.” Done with caution and a critical eye, coverage of limited but promising research can provide a needed dose of optimism for people with MS and their families. Unfortunately, in this case, that journalistic prudence was almost totally missing.

Katherine Bagley is a science, environment and health journalist based in New York City. She is currently working as a reporter for Audubon Magazine.