Tuesday, April 7, 2020

Latest research : Non-N95 face masks cannot completely filter covi

Report by : Gan Yung Chyan
                 / KUCINTA SETIA

Image : North Koreans putting on non-N95 surgical face masks and 100% cotton face mask.

During the COVID-19 (covid, in short) pandemic, people usually wear masks when they go out, and the demand for masks around the world is overwhelming. However, an experimental report published in the American medical journal "Annals of  Internal Medicine" on 6 April 2020 showed that the medical masks or ordinary cloth masks that are traditionally used to filter influenza virus cannot completely block the virus SARS-CoV-2 (covi, in short).

In the letter report entitled "Effectiveness of Surgical and Cotton Masks in Blocking SARS-CoV-2: A Controlled Comparison in 4 Patients" (https://annals.org/aim/fullarticle/2764367/effectiveness-surgical-cotton-masks-blocking-sars-cov-2-controlled-comparison?searchresult=1)  contributed by South Korean researchers, a small-scale experiment was conducted in two hospitals in Seoul, South Korea, to find out if the various masks can filter covi. The researchers found 4 patients diagnosed with covid who provided informed consent to participate in the experiment. They were asked to put on disposable surgical masks, with no surgical masks, with 100% cotton face masks and with no cotton face masks. The researchers placed a separate petri dish 18 cm away from each patient and let them cough 5 times.

The experimental results show that neither medical masks nor cloth masks can completely filter the virus. Not only will covi be scattered in the negative pressure isolation room, but the number of viruses in the outer layer of each mask is more than the those on the inner layer. Leakage is due to the fact that the particles of covi are too small to penetrate the mask.

It is worth mentioning that this experiment did not test the protective properties of the N95 mask. The experiment also does not reflect the actual transmission of infection from covid patients wearing different types of face masks. It is not known whether masks shorten the travel distance of droplets during coughing. Further study is needed to assess whether these masks decrease virus transmission from asyptomatic individuals or those with suspected covid who are not coughing.

The practicality of the respective face masks still needs more in-depth experiments and research.

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