這篇文不是針對健康的人做實驗,參考就好不要恐慌
這個實驗是針對感染者,口罩無法防止感染者咳嗽產生的病毒,沒有針對健康的人戴口罩能防護到多少來做實驗,又想起SARS對於口罩的講法...保持社交距離應該是關鍵
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新冠肺炎(COVID-19)肆虐全球，許多專家呼籲民眾常洗手、戴口罩，可有效阻絕病毒。不過最新研究卻發現，「無論是醫療口罩或棉口罩，都無法有效過濾病毒。」雖未顯示穿戴口罩是否減低飛沫飛行的距離，也未測試N95口罩的防護性，詳細內容仍待進一步研究，但「口罩的實用性」仍引起外界關注。
根據外媒報導，美國醫學期刊「內科學年刊」近日有一份實驗報告，內容顯示「無論是醫療口罩或是布口罩都無法完全過濾病毒」。該研究以南韓首爾的2間醫院為實驗地點，找來4名新冠肺炎確診病患進行對照，並將培養品放在距離病患18公尺的地方，請患者咳嗽5次。結果發現，「病患佩戴的口罩外層，比內層的污染來得多」，顯示新冠病毒可穿透防護，到達口罩外層，並散布至環境中。
雖然實驗範圍小，也僅使用醫療口罩及布口罩，未使用N95口罩進行實驗，實驗報告也沒有說明病毒外漏原因；目前尚不明白是否與「患者咳嗽力道」或「病毒大小」有關。但若依照實驗結果來看，「口罩無法有效過濾病毒」，恐顛覆以往人們對於防疫方法的認知。
https://tw.news.yahoo.com/%E9%86%AB%E7%94%A8%E5%8F%A3%E7%BD%A9%E6%93%8B%E4%B8%8D%E4%BD%8F%E6%96%B0%E5%86%A0%E5%82%B3%E6%92%AD-%E7%BE%8E%E7%A0%94%E7%A9%B6-%E7%97%85%E6%AF%92%E6%81%90%E7%A9%BF%E9%80%8F%E9%98%B2%E8%AD%B7-070556312.html
中文沒有全部翻譯,原文在這邊
https://annals.org/aim/fullarticle/2764367/effectiveness-surgical-cotton-masks-blocking-sars-cov-2-controlled-comparison?searchresult=1
個人積分：10419分
文章編號：77109528
個人積分：78分
文章編號：77109742
個人積分：580分
文章編號：77109783
個人積分：10419分
文章編號：77109788
個人積分：135分
文章編號：77109819
個人積分：10419分
文章編號：77109844
個人積分：4370分
文章編號：77109860
oyc4388 wrote:原文如下。沒看到『培養品放在距離病患18公尺的地方』的描述。
找來4名新冠肺炎確診病患進行對照，並將培養品放在距離病患18公尺的地方，請患者咳嗽5次
應該是20cm...
Effectiveness of Surgical and Cotton Masks in Blocking SARS–CoV-2: A Controlled Comparison in 4 Patients
Background: During respiratory viral infection, face masks are thought to prevent transmission (1). Whether face masks worn by patients with coronavirus disease 2019 (COVID-19) prevent contamination of the environment is uncertain (2, 3). A previous study reported that surgical masks and N95 masks were equally effective in preventing the dissemination of influenza virus (4), so surgical masks might help prevent transmission of severe acute respiratory syndrome–coronavirus 2 (SARS–CoV-2). However, the SARS–CoV-2 pandemic has contributed to shortages of both N95 and surgical masks, and cotton masks have gained interest as a substitute.
Objective: To evaluate the effectiveness of surgical and cotton masks in filtering SARS–CoV-2.
Methods and Findings: The institutional review boards of 2 hospitals in Seoul, South Korea, approved the protocol, and we invited patients with COVID-19 to participate. After providing informed consent, patients were admitted to negative pressure isolation rooms. We compared disposable surgical masks (180 mm × 90 mm, 3 layers [inner surface mixed with polypropylene and polyethylene, polypropylene filter, and polypropylene outer surface], pleated, bulk packaged in cardboard; KM Dental Mask, KM Healthcare Corp) with reusable 100% cotton masks (160 mm × 135 mm, 2 layers, individually packaged in plastic; Seoulsa).
A petri dish (90 mm × 15 mm) containing 1 mL of viral transport media (sterile phosphate-buffered saline with bovine serum albumin, 0.1%; penicillin, 10 000 U/mL; streptomycin, 10 mg; and amphotericin B, 25 µg) was placed approximately 20 cm from the patients' mouths. Patients were instructed to cough 5 times each onto a petri dish while wearing the following sequence of masks: no mask, surgical mask, cotton mask, and again with no mask. A separate petri dish was used for each of the 5 coughing episodes. Mask surfaces were swabbed with aseptic Dacron swabs in the following sequence: outer surface of surgical mask, inner surface of surgical mask, outer surface of cotton mask, and inner surface of cotton mask.
The median viral loads of nasopharyngeal and saliva samples from the 4 participants were 5.66 log copies/mL and 4.00 log copies/mL, respectively. The median viral loads after coughs without a mask, with a surgical mask, and with a cotton mask were 2.56 log copies/mL, 2.42 log copies/mL, and 1.85 log copies/mL, respectively. All swabs from the outer mask surfaces of the masks were positive for SARS–CoV-2, whereas most swabs from the inner mask surfaces were negative (Table).
Table. SARS–CoV-2 Viral Load in Patient Samples, Petri Dishes, and Mask Surfaces
Discussion: Neither surgical nor cotton masks effectively filtered SARS–CoV-2 during coughs by infected patients. Prior evidence that surgical masks effectively filtered influenza virus (1) informed recommendations that patients with confirmed or suspected COVID-19 should wear face masks to prevent transmission (2). However, the size and concentrations of SARS–CoV-2 in aerosols generated during coughing are unknown. Oberg and Brousseau (3) demonstrated that surgical masks did not exhibit adequate filter performance against aerosols measuring 0.9, 2.0, and 3.1 μm in diameter. Lee and colleagues (4) showed that particles 0.04 to 0.2 μm can penetrate surgical masks. The size of the SARS–CoV particle from the 2002–2004 outbreak was estimated as 0.08 to 0.14 μm (5); assuming that SARS-CoV-2 has a similar size, surgical masks are unlikely to effectively filter this virus.
Of note, we found greater contamination on the outer than the inner mask surfaces. Although it is possible that virus particles may cross from the inner to the outer surface because of the physical pressure of swabbing, we swabbed the outer surface before the inner surface. The consistent finding of virus on the outer mask surface is unlikely to have been caused by experimental error or artifact. The mask's aerodynamic features may explain this finding. A turbulent jet due to air leakage around the mask edge could contaminate the outer surface. Alternatively, the small aerosols of SARS–CoV-2 generated during a high-velocity cough might penetrate the masks. However, this hypothesis may only be valid if the coughing patients did not exhale any large-sized particles, which would be expected to be deposited on the inner surface despite high velocity. These observations support the importance of hand hygiene after touching the outer surface of masks.
This experiment did not include N95 masks and does not reflect the actual transmission of infection from patients with COVID-19 wearing different types of masks. We do not know whether masks shorten the travel distance of droplets during coughing. Further study is needed to recommend whether face masks decrease transmission of virus from asymptomatic individuals or those with suspected COVID-19 who are not coughing.
In conclusion, both surgical and cotton masks seem to be ineffective in preventing the dissemination of SARS–CoV-2 from the coughs of patients with COVID-19 to the environment and external mask surface.
個人積分：10419分
文章編號：77109894
個人積分：341分
文章編號：77109979
後來的 中國武漢肺炎 疫情開始，專家認為 一般的民眾，只是生活上的接觸，一般的醫療等級的口罩，就足以防止 飛沫、呼吸道的分泌物 的阻擋。而且..... 醫療等級的口罩 就已經有一層的防水層，只要正確的使用口罩，就足以應付 中國武漢肺炎病毒的感染。 我們更應該重視 多洗手、戴口罩脫口罩，避免去碰觸當最前面的感染層，手也要避免碰觸口鼻， 脫口罩之後也要洗手。
oyc4388 wrote:
醫用口罩擋不住新冠傳播？美研究：病毒恐穿透防護(恕刪)
個人積分：275分
文章編號：77110007
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