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Thread: Review of "A cluster randomised trial of cloth masks compared with medical masks in healthcare workers," published in The BMJ in 2015. Do we #WearAMask? Do we #WearADamnMask? Read on! (1/9) https://bmjopen.bmj.com/content/5/4/e006577
This study was to evaluate the efficacy of cloth masks for hospital healthcare workers (HCWs), by looking at these outcomes: clinical respiratory illness (CRI), influenza-like illness (ILI), and laboratory-confirmed respiratory virus infection. (2/9)
The conclusion of the study was that the authors caution against the use of cloth masks, as they may *increase* risk of infection in the healthcare setting. They are therefore not recommended for HCWs. (3/9)
Here are three types of masks that were tested:
1) Cloth masks
2) Control (standard practice, which could be usage of either type of mask, but not both)
3) Medical mask (conforms to the respiratory standard AS/NZS 1716, see examples below)
(4/9)
1) Cloth masks
2) Control (standard practice, which could be usage of either type of mask, but not both)
3) Medical mask (conforms to the respiratory standard AS/NZS 1716, see examples below)
(4/9)
In 3 outcomes measures, cloth masks performed worse. Rate of ILI was statistically significantly higher in the cloth masks compared to medical masks and the control group. Medical masks also performed significantly better than cloth masks re: laboratory-confirmed virus. (5/9)
The authors were unable to determine whether the differences between the medical and cloth mask arms were due to a protective effect of medical masks or a detrimental effect of cloth masks, as the IRB did not allow for an "unmasked" control group. (6/9)
One final result of note: Penetration of cloth masks by particles was almost 97% and medical masks 44%. You aren't saving the world by wearing a bandanna over your nose and mouth, despite what you've heard. (7/9)
Since this study occurred in 2015, the authors have written a response to their work in light of the COVID-19 pandemic. The authors do *not* recommend that HCWs work without appropriate medical respiratory protection. (8/9) https://bmjopen.bmj.com/content/5/4/e006577.responses#covid-19-shortages-of-masks-and-the-use-of-cloth-masks-as-a-last-resort
So, can we please stop treating masks like they're magical force fields? You might be hurting yourself by wearing a mask, and you're definitely hurting others by assaulting others that do not wish to wear a mask. So calm down, Karen. (9/9)
Unroll please, @threadreaderapp.
