ME, which is also known as CFS and ME/CFS, is a complex and disabling disease affecting up to a million people worldwide. It is more prevalent than HIV infection and twice as common as rheumatoid arthritis, yet remains one of the most misunderstood conditions.

This is partly because there is no laboratory test to confirm the diagnosis and because people who have ME are frequently misdiagnosed with other illnesses. But it is also because many healthcare professionals have not been educated about ME/CFS and do not understand its biological underpinnings.

The symptoms of ME are largely physical and include fatigue, post-exertional malaise (PEM), unrefreshing sleep and cognitive impairment. Symptoms can be triggered by many different activities, from going out for a jog to eating an apple. In more severe cases, the effects can be so severe that they leave a person housebound or bedbound. ME is a multifactorial disorder, and research is ongoing to determine the cause of the illness.

It is not yet understood why some people develop ME and others do not, but it is thought to be triggered by a viral or bacterial infection. Herpesviruses, enteroviruses and COVID-19 are among the infections that have been implicated. It is also possible that certain genes make some people more likely to develop ME.

There is no cure for ME, but it can be managed by reducing activity levels, taking medication and using physiotherapy to help with symptoms. It is also important to address any comorbidities that are present – for example, fibromyalgia, postural orthostatic tachycardia syndrome, gastroparesis, mast cell disorders and secondary depression.

Research is underway to find safe and effective treatments, but at the moment there is no universally effective medicine. There is no evidence that ME causes or contributes to other health problems, although it does have a negative impact on quality of life, and 25% of people with ME are housebound or bedbound.

ME is more common in women than men, and it affects all ages, sex and socioeconomic groups. It is estimated that around a million people worldwide live with ME, and the number of people with ME has been rising rapidly.

We need to work together to increase awareness and support to ensure that ME/CFS is recognised as the serious chronic condition that it is. This means raising awareness, funding and education. It is also vital to encourage the right policy environment and change in behaviour so that healthcare professionals can better recognise ME/CFS and support patients. If you are a healthcare professional, please consider joining #MEAction to support our campaign to accelerate the discovery of safe and effective ME/CFS treatments.