Stanford University, USA, give a help about which materials should be used, using a scientific article published in 2013, where the use of homemade masks was compared with the N95 or PFF2 surgical masks (according to North American or European standards, respectively) – the most professional and effective, which should be reserved for healthcare professionals. In that study, entitled “Testing the effectiveness of homemade masks: could they protect us in the event of a flu pandemic?” several materials were studied and compared with the effectiveness of PFF2. Stanford compiled these conclusions, in the following graph, where it can be seen that some of the most effective materials are vacuum cleaner filters, tablecloths and cotton t-shirts.
Comparison of the effectiveness of various materials for homemade masks (D.R. Stanford University)
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Any mask made from one of these materials must, however, be subject to a series of precautions. The CDC recommends that these masks be regularly washed, in a common washing machine with detergent, and that the safety rules are respected when removing the mask, not touching the eyes, nose and mouth and immediately washing the hands afterwards. In addition, they should not be used by children under two years of age, by people with breathing problems or by people who are unable to remove them on their own. They are “an additional and voluntary public health measure”.
To be more effective, the CDC also recommends that they cover the entire mouth and nose, but that they are not too tight, that they have several layers of fabric and that they are made of a material that does not shrink when washing.
Even if you followed all the recommendations, it is important to remember that having a mask does not guarantee that, from here on, you are completely protected from Covid-19. What we can know is that we are probably contributing to reducing the risk of spreading the virus, if we are carriers of it without knowing it. And even that, it is not 100% guaranteed – it is necessary to know how to use the mask and, above all, not to fail to have all other protective measures, especially social distance.
“The masks, by themselves, do not stop the pandemic. There are no blacks and whites, there are no ‘magic bullets’ ”, warned Tedros Adhanom Ghebreyesus, director of WHO, on Monday afternoon, saying that “there is little data available” about the effectiveness of masks in containing this virus and that we should prevent masks from missing from health professionals. However, he said that WHO would issue new recommendations in this regard and called on countries that are taking the measure to study it to the fullest.
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