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The recent Reuters article about the illness, or cluster of illnesses, variously called CFS, ME, CFS/ME and ME/CFS was problematic for many reasons. One of them was the information included from the US Centers for Disease Control and Prevention. In explaining why the CDC dropped its longstanding recommendations for cognitive behavior therapy and graded exercise therapy, Dr Elizabeth Unger, chief of the chronic viral diseases branch, repeated the tired trope that the agency believed people had “misinterpreted” what it meant.
It is long past time for the CDC to drop this unconvincing claim. As a public health agency, it has a responsibility to acknowledge when it has made mistakes, as it has in this case, rather than advancing absurd arguments to cover its tracks.
Let’s review the history. Prior to the summer of 2017, the CDC removed its continuing medical education module on the illness, which included references to PACE. Although the agency left recommendations for CBT and GET in place on the website, it positioned them as generic management strategies. This was clearly nonsense–a face-saving way of not admitting error. For one thing, the agency does not routinely recommend CBT and GET as generic management strategies for other chronic illnesses. For another, the CME module had linked the treatment recommendations directly to PACE; only after the module was removed were CBT and GET deemed to be generic management strategies.
When the CDC removed the recommendations themselves two years ago, it did so quietly. The change became public after I noticed it mentioned on an advocacy forum and then questioned the agency. At that point, I received a statement explaining that the recommendations had been removed because people had expressed “confusion” about what the agency meant by CBT and GET. Apparently Dr Unger conveyed a similar message to Kate Kelland, the Reuters reporter.
Note to Dr Unger: No one who knows anything about this field misinterpreted what the CDC meant in recommending CBT and GET as treatments. By pushing this untenable argument, you make yourself and the agency look ridiculous. Please just acknowledge that the CDC got it wrong in endorsing PACE and the CBT/GET paradigm in the first place.
As clearly explained in the 2011 PACE paper in The Lancet and other publications, the two treatments were based on the unproven theory that patients’ persistent symptoms were perpetuated by deconditioning. This deconditioning was itself, per the theory, caused by sedentary behavior arising from unhelpful beliefs about having a physical illness that could be exacerbated by excess activity. The goal of the treatments was to reverse these unhelpful beliefs and the attendant deconditioning through a mix of psychological and behavioral strategies.
Yet PACE was an open label trial that relied on subjective outcomes—a study design that generates an unknown amount of bias. The trial also used a broad definition for the illness that has been shown to identify many people who don’t actually have it. Moreover, the study’s reported success on the subjective measures was possible only because of dramatic changes to the methods of assessing these outcomes. Finally, in PACE, the objective outcomes all failed to match the subjective reports—a failure downplayed by the investigators and their enablers.
The CDC has adopted the new definition of the disease presented in a 2015 report from the US Institute of Medicine, now the National Academy of Medicine. The 2015 report found that the illness is associated with neurological, immunological and energy metabolism impairments that cannot be attributed to the effects of deconditioning. According to the new definition, the cardinal symptom is not fatigue per se but “exertion intolerance”—the tendency to suffer relapses after minimal activity, often called “post-exertional malaise.”
And if exertion intolerance is the cardinal symptom, then a program of steadily increasing exercise like GET would clearly be contra-indicated. So would the form of CBT used in PACE, which was designed to alleviate patients of the supposedly unhelpful beliefs about their illness that purportedly kept them from engaging in activity.
For years, the CDC—the country’s lead public health agency–placed its faith in PACE. Yet the study was riddled with methodological anomalies that first-year epidemiology students can spot. In PACE, for example, participants could be “recovered” or “within normal range” on key outcome thresholds at baseline, before any treatment at all—a feature that should have disqualified any trial from getting published. These problems were immediately evident to patients. Why did the CDC fail to notice?
The CDC has evaded answering this question by pretending that readers “misinterpreted” its advice rather than admitting that agency officials themselves screwed up big time. And the CDC’s refusal to provide an honest accounting—to state that it removed the CBT and GET recommendations because the science it had previously cited could not in fact be defended—is disturbing. This abdication of responsibility allows biased and misguided reporters like Kelland to suggest, without evidence beyond the speculations of PACE defenders, that the agency acted under pressure and intimidation from science-illiterate patients.
The CDC’s statements and actions matter because other medical institutions and public health agencies follow its cues. As soon as the agency removed the CBT and GET recommendations in 2017, it should have launched a serious outreach effort to alert medical providers of the change. That it did not helps explain why major centers like the Mayo Clinic have continued to push ME/CFS patients toward psychotherapy and exercise-based treatments despite the lack of quality evidence to support their use. (The CDC has recently updated its website material for medical professionals, but it has still done far too little to counter the potential damage from its past recommendations.)
Given the history, I suppose it is not surprising that the CDC and Dr Unger continue to disappoint in this domain. But it is nonetheless very, very dispiriting. Even after all this time, they appear unable to act in ways deserving of their leadership roles.
When viruses are introduced into a new population, selection pressures can lead to evolution of both pathogen and host. The pathogen must adapt to a new host, while the latter can become resistant to infection, leading to an arms race. An archetypal example of such host-pathogen evolution is illustrated by the attempt to control rabbit populations in Australia by the release of a pathogenic virus. Recent work 
by Gertrud U. Rey