ME/CFS research: where the science is heading

The COVID-19 pandemic brought a large number of new Long Covid patients into the medical system. Because a significant proportion of people with Long Covid meet the criteria for ME/CFS, the medical world has had to engage with post-viral illness in a way it had not previously.

That shift in attention is benefiting ME/CFS research. Investigators are now studying the mechanics of post-viral illness at a scale that was not possible before.

On 13 November 2025, the German government committed €500 million to a ten-year National Decade Against Post-Infectious Diseases, covering ME/CFS and Long Covid research from 2026 to 2036. It is the largest public funding commitment for post-infectious disease research, including ME/CFS, to date.

In the UK, the DecodeME study, jointly funded by the MRC and NIHR, is the largest genetic study of ME/CFS in the world, comparing the DNA of more than 15,000 people with ME/CFS against around 260,000 people without the condition. The Netherlands, Australia, and Canada have also committed dedicated public funding.

The picture is not uniformly positive. The US remains significantly underfunded relative to the scale of the illness. France, Italy, Spain, and most of Asia have little or no dedicated public funding. But for the first time in 40 years, the direction of travel is the right one.

In 2025, DecodeME reported its first findings. The analysis identified eight genetic signals: small but consistent differences in the DNA of people with ME/CFS compared with the general population.

These signals fall into two groups. Some involve the immune system, including genes that govern how the body responds to infection. Others involve the nervous system, and one sits in a region already associated with chronic pain. Researchers found no shared genetic basis with depression or anxiety.

Because a person’s DNA does not change after they become ill, these differences reflect causes rather than consequences. That is what gives the study its weight: it offers biological evidence for an illness that was dismissed as psychological for decades, and it aligns with what people with ME/CFS have long reported about their own bodies.

The findings carry real caveats. They are published as a preprint and have not yet completed peer review, so details may change. The signals also did not replicate strongly in other genetic databases, which means independent confirmation is still needed. Genetic results of this kind point to biological pathways worth investigating. They do not, on their own, produce a diagnostic test or a treatment.

DecodeME showed where the answers might lie. A follow-on study, Sequence ME and Long Covid, is designed to look more closely. Led by the same team, it will read participants’ entire genetic code rather than the common variants DecodeME examined, using a method called long-read whole-genome sequencing.

In May 2026, the project secured £4.75 million in UK government funding, through the Medical Research Council, to begin sequencing the DNA of 6,000 people with ME/CFS already collected through DecodeME. This is the first stage of a planned £20 million effort to sequence the genomes of 9,000 people with ME/CFS and 9,000 people with Long Covid. It is expected to become the largest study of its kind for any disease.

For people with ME/CFS, this changes nothing about daily life today. What it adds is depth: the same samples that produced DecodeME’s first results will now be read in full, so researchers can begin to pinpoint the specific genes involved.

Researchers are investigating several theories about what goes wrong in ME/CFS. Several of these theories now have support from DecodeME’s genetic findings.

Energy and the Brain

• Mitochondrial dysfunction. Research is examining why cells fail to produce energy normally and why exertion triggers the kind of collapse seen in PEM.
• Neuroinflammation. Advanced brain imaging has found evidence of neuroinflammation in some people with ME/CFS. These findings support the hypothesis of a physical neurological basis for the illness, though research in this area is ongoing and not yet definitive.

Immunity and the Gut

• Autoimmunity and viral persistence. Researchers are investigating whether ME/CFS involves an autoimmune process, or whether viral material remains in the body’s tissues after the initial infection has cleared.
• The gut microbiome. Studies consistently find differences in the gut bacteria of people with ME/CFS, particularly in bacteria associated with inflammation and energy regulation.

These are active research areas, not settled conclusions. Findings are promising but preliminary.

A single treatment that resolves ME/CFS is not an imminent prospect.

Researchers are running clinical trials on existing medications to determine whether any can reliably ease specific symptoms. The realistic near-term goal is not a cure. It is finding treatments that raise the baseline and return some quality of life to people with ME/CFS.

There are now more researchers working on this illness, more funding behind them, and more international coordination than at any previous point. For people living with ME/CFS today, that does not change the immediate picture. But it does mean the field is no longer standing still.