A team of New Zealand researchers (University of Otago, in a paper supported by ANZMES) has published a theory paper in 2022 looking at why ME/CFS and Long COVID symptoms persist long-term and why relapses happen — even from small, everyday stresses. It’s a “hypothesis” paper, meaning it’s not the final word, but it pulls together a lot of existing evidence into one clear, plausible explanation. Here’s what it might mean for you.
The researchers propose that after the illness starts (from a virus, infection, chemical exposure, surgery, or another major stressor), the body’s initial inflammation response doesn’t switch off properly. Instead of settling down like it does in most people, that inflammation finds a way into the brain — either along nerve pathways or through a “leakier” blood-brain barrier. Once in the brain, it sets off ongoing low-level brain inflammation (neuroinflammation), particularly around the area that controls your stress response. This creates a two-way loop between body and brain that keeps the illness going and drives the relapse–partial recovery cycles so many of us know well.
What this means for people with ME/CFS
- It’s biological, not “in your head.” This adds to the growing body of evidence that ME/CFS and Long COVID involve real, measurable changes in the immune system and the brain — not deconditioning, not anxiety, not a psychological issue.
- It may explain why small things trigger a crash. If your brain’s stress-control centre (the hypothalamus) has become oversensitive because of this ongoing inflammation, it makes sense that a mildly stressful day, a change in temperature, or even a glass of wine can tip you into a relapse when it wouldn’t affect someone without ME/CFS.
- It may explain brain fog, poor sleep, and “sickness” feelings. The same stress-control centre also helps regulate sleep, temperature, and energy use — so if it’s not working properly, that could explain the cluster of symptoms beyond fatigue: cognitive fog, unrefreshing sleep, and that generally unwell “sickness response” feeling.
- It supports why pacing matters. If everyday stressors (physical, cognitive, or emotional) can reactivate this inflammatory loop and trigger relapse, that lines up with what pacing and energy management are designed to protect against — avoiding the stress spikes that seem to feed the cycle.
- Long COVID and ME/CFS look like they work the same way. Even though Long COVID comes from a single virus (SARS-CoV-2) and ME/CFS can be triggered by many different causes, the researchers think both conditions likely involve this same brain-inflammation mechanism — which is part of why the symptoms overlap so closely.
- It’s not thought to be degenerative. Unlike conditions such as Alzheimer’s or Parkinson’s, the researchers note ME/CFS doesn’t appear to permanently damage the brain — which means that, in principle, if this mechanism is confirmed and a way is found to calm the inflammation, recovery of function could be possible.
- This is a theory, not a cure — yet. No new treatment comes out of this paper. What it does is give researchers a clearer, testable roadmap (brain scans, spinal fluid studies, long-term tracking of patients from the point of infection) for the work still to come. It’s a foundation-building step, not a finish line.
- It’s homegrown research. This work comes out of the University of Otago and builds on New Zealand’s own long-running ME/CFS research programme, with support from ANZMES — part of a body of local science that continues to take this illness seriously.
Bottom line
This paper doesn’t change anything about how to manage your condition day-to-day, but it adds solid scientific weight to what many of you already know from experience: that ME/CFS and Long COVID are real, biologically driven illnesses with a plausible explanation for the relapse cycles — and that pacing and stress management aren’t just coping strategies, they may be protecting you from actively fuelling the underlying process.
Source: Tate W, Walker M, Sweetman E, et al. “Molecular Mechanisms of Neuroinflammation in ME/CFS and Long COVID to Sustain Disease and Promote Relapses.” Frontiers in Neurology, 2022.
