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Japanese experts suspect neuroimmune disease causing pain, fatigue as COVID-19 aftereffect

A woman who is suspected of having been infected with the coronavirus and later diagnosed with myalgic encephalomyelitis/chronic fatigue syndrome continues to spend most of her day in bed. (Photo courtesy of the individual)

TOKYO -- Many coronavirus patients continue to feel fatigued after they no longer have the virus, so much so that it is difficult for them to carry on with their everyday lives -- a symptom that is believed to be an aftereffect of COVID-19.

    It is highly suspected that such symptoms are caused by a neuroimmune disease called myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Experts in Japan and overseas are sounding the alarm, with one saying, "There is a good chance that the new coronavirus is acting as a trigger." The Mainichi Shimbun looked into the link between COVID-19 and ME/CFS, a disease for which patients are eagerly awaiting the establishment of treatment.

    A woman who is suspected of having been infected with the coronavirus and later diagnosed as with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), shows diagnostic results she received at the time, in this photo provided by the individual.

    A part-time worker in the city of Sagamihara, Kanagawa Prefecture, southwest of Tokyo, developed symptoms including mild fever, headache, shortness of breath and fatigue in March 2020. The 48-year-old woman suspected she was infected with the coronavirus and went to a family physician, but was unable to receive a polymerase chain reaction (PCR) test because her fever did not exceed 37.5 degrees Celsius.

    She was prescribed medicines for a cold, but her condition only got worse to the point that she felt severe pain in her fingers just by holding chopsticks. The following day, the woman couldn't even get up due to physical exhaustion, and had to take a leave of absence from work. In the next six months, tests including blood work and X-rays were conducted on the woman's entire body, but what was causing her weariness remained a mystery.

    In December 2020, however, the woman was told it was highly likely she had contracted COVID-19, and in January 2021 she was diagnosed with ME/CFS. Though her medication has alleviated her pain, she still spends most of her day in bed.

    ME/CFS is a disease of unknown cause, which makes it difficult for patients to live their everyday lives due to symptoms such as fatigue, trouble breathing and sleepiness that don't go away. Furthermore, patients can continue to feel pain all over their bodies and suffer from loss of concentration and deterioration in memory for six months or more.

    The 48-year-old woman began to have a hard time remembering things, such as forgetting if the clothes she wore a day before were her own, and riding the train to a terminal station on the opposite end from where she lives.

    Doctor Takashi Yamamura at the National Center of Neurology and Psychiatry who is well informed about ME/CFS explained, "People who are infected with severe acute respiratory syndrome (SARS) coronavirus and other viruses have developed the disease, and the novel coronavirus may also be a trigger." Yamamura has diagnosed about 20 patients who he suspects are suffering from the aftereffects of COVID-19 with ME/CFS.

    A report compiling information on the link between the new coronavirus and ME/CFS was published in an American academic journal on neurology last summer, and the U.S. has apparently already launched large-scale research into the matter.

    Research has found that ME/CFS causes abnormalities in the central nervous system of the brain, which plays an important role in cognition and language. Yamamura said, "Even after the body is rid of the virus, there may be an overactive immune response causing an inflammatory reaction in the brain. The spread of the coronavirus will likely increase the number of ME patients, but rest and early treatment can prevent the symptoms from becoming severe."

    The Japan ME Association, an incorporated nonprofit organization consisting of ME patients, conducted a survey on suspected COVID-19 patients from May to August last year and received answers from 326 people. It apparently revealed that 27.9% of respondents met the diagnostic criteria for ME/CFS such as headache and dizziness.

    Chairperson of the association, Mieko Shinohara, told the Mainichi, "If we understand the mechanism of how patients develop ME after being infected with the new coronavirus, it will lead to the development of a treatment. We would like Japan to advance research and establish a treatment method."

    Of the 326 respondents, 213 people were unable to take PCR tests or tested negative. According to Japan ME Association's online survey, the main impact on the lives of the respondents included: 40.5% not being able to return to work or school; 12.6% being close to bedridden; 11.3% not being able to look after themselves; and 3.7% needing to relearn basic actions such as swallowing and walking.


    In Japan, there are an estimated 300,000 patients with ME/CFS, a neuroimmune disease of the entire body which can cause symptoms including fatigue; sleeping disorder; losing the ability to think, concentrate and remember; and muscle soreness continuing for at least six months, making it hard for patients to live a healthy social life.

    According to a survey carried out by the Ministry of Health, Labor and Welfare in 2014, around 30% of such patients are bedridden. ME/CFS is not included in the national subsidy for measures against intractable diseases, and the fact that there are only a few specialists in Japan is also a problem.

    In North America and Europe, research has shown that a certain number of patients infected with SARS and EB virus develop ME/CFS.

    (Japanese original by Naomi Hayashi, Lifestyle and Medical News Department)

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