9/21(月) 12:04
CNN.co.jp
透過型電子顕微鏡で撮影した新型コロナウイルス
（ＣＮＮ） 米疾病対策センター（ＣＤＣ）が公式サイトに掲載しているガイダンスを改訂し、コロナウイルスは一般的に、呼吸などによって空気中に漂う飛沫（ひまつ）や微粒子を通じて拡散し得ると指摘した。「新型コロナウイルスを含む空気を浮遊するウイルスは特に感染力が強く、簡単に拡散する」としている。
【画像集】新型コロナ後のエコノミー座席、「乗り心地」と「距離」を両立
ＣＤＣはこれまで同ページの中で、新型コロナウイルスは主に至近距離（６フィート＝約１．８メートル）での人と人との接触や、感染者のせき、くしゃみ、発話によって飛び散る飛沫を通じて感染すると説明していた。
しかし１８日にこの内容を改訂し、新型コロナウイルスは密接な接触のあった人同士で感染するのが最も一般的だとする記述に加えて、「感染者がせき、くしゃみ、発話、呼吸をした際に発生する呼吸器の飛沫やエアロゾルに含まれる形などの微粒子を通じて」拡散することも分かっていると付け加えた。
さらに、そうした粒子を鼻や口、気道、肺を通じて吸い込むと感染を引き起こし得ると述べ、「これはウイルス拡散の主な経路と考えられる」と指摘。「飛沫や大気中の粒子は空気中に滞留して他人に吸い込まれる可能性があり、６フィート以上の距離にも届く（例えば合唱練習や飲食店、フィットネス教室などで）ことを裏付ける証拠は増えている」「一般的に、換気が不十分な屋内環境はこのリスクを増大させる」とした。
感染を防ぐための新たな対策としては、「可能な限り、他人から少なくとも６フィート以上離れる」よう呼びかけ、引き続きマスクの着用や手洗い、消毒の徹底を促した。さらに、症状がある場合は外出せずに隔離措置を講じなければならないと述べ、屋内では浮遊菌を減らすために空気清浄機を使うことを勧告している。
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CDC abruptly removes guidance about airborne coronavirus transmission, says update 'was posted in error'
(CNN) - The US Centers for Disease Control and Prevention on Monday abruptly reverted to its previous guidance about how coronavirus is transmitted, removing language about airborne transmission it had posted just days earlier.
"A draft version of proposed changes to these recommendations was posted in error to the agency's official website. CDC is currently updating its recommendations regarding airborne transmission of SARS-CoV-2 (the virus that causes COVID-19). Once this process has been completed, the update language will be posted," Jason McDonald, a CDC spokesman, said in a response emailed to CNN.
The guidance had been quietly updated on Friday, according to the CDC's website. CNN was first to report the change on Sunday. The CDC responded to CNN just before noon on Monday to say it was reverting to the previous guidance.
Despite several studies that have shown the novel coronavirus can spread through small particles in the air, the CDC page now says that Covid-19 is thought to spread mainly between people in close contact -- about 6 feet -- and "through respiratory droplets produced when an infected person coughs, sneezes or talks." This is the same language it posted months ago.
,In language posted Friday and now removed, CDC said Covid-19 most commonly spread between people who are in close contact with one another, and went on to say it's known to spread "through respiratory droplets or small particles, such as those in aerosols, produced when an infected person coughs, sneezes, sings, talks or breathes."
These particles can cause infection when "inhaled into the nose, mouth, airways, and lungs," the agency said. "This is thought to be the main way the virus spreads."
"There is growing evidence that droplets and airborne particles can remain suspended in the air and be breathed in by others, and travel distances beyond 6 feet (for example, during choir practice, in restaurants, or in fitness classes)," the page said in the Friday update, which has since been removed. "In general, indoor environments without good ventilation increase this risk."
In the Friday update, the CDC had added new measures to protect yourself in others, including recommendations to use air purifiers to reduce airborne germs in indoors spaces and clear guidance to "stay at least 6 feet away from others, whenever possible." The updated CDC page had also changed language around asymptomatic transmission, shifting from saying "some people without symptoms may be able to spread the virus" to saying "people who are infected but do not show symptoms can spread the virus to others." That language has now been removed.
Also on Friday, CDC updated its coronavirus testing guidance to stress that anyone who has been in contact with an infected person should be tested for coronavirus. A controversial earlier update was not written by CDC scientists and posted online before it had undergone the normal scientific review process, two sources confirmed to CNN last week.
CNN reported last week that US Health and Human Services communications officials appointed by President Trump had recently pushed to change language of weekly science reports released by the CDC so as not to undermine Trump's political message, according to a federal health official. Officials within HHS had defended the demand, saying the CDC fell under the agency's umbrella and that all communications and public documents needed to be cleared at the top. CDC Director Dr. Robert Redfield said last week "at no time has the scientific integrity" of these reports been compromised.
에어로졸(대기 중에 떠도는 미세한 입자)이 신종 코로나바이러스 감염증(신종 코로나)을 전파하는 경로 중 하나라고 중국 상하이(上海) 당국이 밝혀 논란이 일고 있다. 중국 중앙 정부는 하루 만에 에어로졸 전파의 증거가 없다고 진화에 나섰지만 공기 중 감염 여부를 둘러싼 논란이 일고 있다.
쩡췬(曾群) 상하이 민정국 부국장은 8일 기자회견에서 “신종 코로나의 주요 전파 경로는 (비말을 통한) 직접 전파, 에어로졸 전파, 접촉 전파로 확정할 수 있다”고 밝혔다. 에어로졸 전파란 에어로졸에 포함된 바이러스가 공기 중에 떠다니다가 에어로졸의 수분이 마른 뒤 흡입될 때 일으키는 감염을 말한다.
에어로졸 전파의 가능성을 인정할 경우 기존 비말 감염보다 감염 범위가 넓어지게 된다. 비말은 무거워서 2m 이내로 튀고 가라앉는 반면 에어로졸은 가벼워서 멀리 퍼진다. 사무실 등 밀폐된 실내 공간이라면 에어로졸을 통한 집단 감염도 가능하다.
이로 인해 공기 중 감염에 대한 불안이 확산되자 중국 정부는 에어로졸 감염 가능성을 부인했다. 9일 국무원 브리핑에 등장한 중국질병예방통제센터(CDC) 전문가는 “아직까지는 에어로졸 전파를 보여주는 증거가 없다”고 밝혔다. 하지만 CDC는 최근 발간한 신종 코로나 자료에서 에어로졸 전파를 3대 전파 경로로 적시한 것으로 확인됐다.
우리나라는 에어로졸을 통한 공기 중 감염을 일반적인 전파 경로로 인정하지 않고 있다. 정은경 질병관리본부장은 9일 “현재까지 모든 전문가의 의견은 지역사회에서 공기 전파 가능성이 거의 없다는 것이며, 질본 의견도 그렇다”면서 “드물게 병원에서 호흡기 시술 과정에서 에어로졸이 발생할 수 있지만 제한적인 환경 내에서만 가능한 것”이라고 말했다.
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