Research press release

疫学:軽症患者でのCOVID-19後遺症(long COVID)を評価する

Nature Medicine

Epidemiology: Long COVID in individuals with mild illness assessed

軽症の新型コロナウイルス感染症(COVID-19)で自宅隔離となった若年成人(16歳〜30歳)の半数以上が、最初の感染の後の6か月に、継続的な呼吸困難、味覚と嗅覚の喪失、倦怠感、集中力や記憶力の低下などの症状を経験していることが、ノルウェーのベルゲンで行われた312人の患者集団の調査で明らかになった。この報告はNature Medicine に掲載される。

COVID-19罹患後に長く続く合併症は、重症となって入院した患者では広く見られている。しかし、このlong COVIDと呼ばれている後遺症が、軽症から中等症の患者ではどの程度のものなのかは、よく分かっていなかった。

COVID-19の軽症患者の長期的な症状を調べるため、Bjørn Blombergたちは312人の患者の追跡調査を行った。これは、ノルウェーのパンデミック第一波の際のベルゲンでの全症例の82%に当たる。312人の内訳は、自宅隔離患者247人と入院患者65人で、平均年齢は46歳、51%が女性である。調査に参加した患者は2か月目と6か月目に医療機関に赴き、医師が問診を行って症状を記録した。6か月の時点で、全患者の61%で症状が継続しており、これは感染開始時の症状の重さとは関連がなかった。自宅隔離となった若年成人のうち61人(52%)では、6か月の時点で何らかの症状、すなわち味覚と嗅覚の喪失(28%)、倦怠感(21%)、呼吸困難(13%)、認知障害(13%)、記憶障害(11%)などが続いていた。


More than half of home-isolated young adults (aged 16–30 years) with mild COVID-19 experienced persistent breathing trouble, loss of taste and smell, fatigue or impaired concentration and memory 6 months after their initial infection in a study of 312 patients in Bergen, Norway, published in Nature Medicine.

Long-term complications following COVID-19 are common in hospitalised patients with severe symptoms, but the burden of so-called ‘long COVID’ in mild to moderately ill patients is not well understood.

To assess the long-term symptoms of individuals with mild COVID, Bjørn Blomberg and colleagues followed up with a group of 312 patients, who made up 82% of the total cases in Bergen during the first pandemic wave in Norway. This group comprised 247 home-isolated and 65 hospitalised individuals with a median age of 46 years, 51% of whom were women. Participants went to a clinic on a bimonthly basis to have their symptoms recorded by interview with a physician. At 6 months, 61% of all patients had persistent symptoms, which were independently associated with the severity of the initial illness. A total of 61 (52%) of home-isolated young adults continued to have symptoms at 6 months, including loss of taste and smell (28%), fatigue (21%), trouble breathing (13%) and impaired cognition (13%) and memory problems (11%).

The authors express their concern that some non-hospitalised young people suffer from potentially severe symptoms for as long as half a year after infection, and note that the high occurrence of persistent fatigue in COVID-19 patients is striking and appears to be higher than that observed after other common infections, such as influenza and Epstein–Barr virus mononucleosis. Considering the millions of young people infected during the ongoing pandemic, the authors argue for comprehensive infection control, population-wide mass vaccination and further investigation into the spectrum of symptoms in milder cases.

doi: 10.1038/s41591-021-01433-3


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