Asthma and coronavirus disease - COVID-19
Each of these arguments can be challenged. The first one, for instance, is invalid on the basis that masks have been shown to be useful in other epidemics, such as SARS: the fact that they have not yet been demonstrated to be so in the context of COVID-19 does not mean that they never will. Wikipedia defines the precautionary principle as "a strategy for approaching issues of potential harm when extensive scientific knowledge on the matter is lacking." Given the rate at which the virus is spreading, coupled with the high fatality rates in specific subgroups, surely, precautionary measures are desirable at this point.
Their second argument states that masks should be reserved for healthcare workers. The solution to the inadequacy of mask supplies is to manufacture more, not withhold existing ones from a vulnerable populace. Professor Trisha Greenhalgh at the University of Oxford and colleagues hypothesize that, given the political will, existing manufacturing capacity can be repurposed to churn out any volume of masks required to provide as many as are required.
Thirdly, against a background of severe and spreading infection, the public can be easily taught to use masks consistently and properly. The final argument does not take into account the efficiency with which the public has been educated as to the danger of the COVID-19 virus. In essence, it is highly unlikely that, given an extra layer of protection, that they will neglect the preexisting ones or go to the trouble of learning how to most efficiently use both.
The masks are unlikely to be too much of a nuisance: the CDC states that they could have a "relatively small impact on social and economic life." Putting all the facts together, several researchers have independently concluded that there is no longer a need to wait for randomized controlled trials before advising the general use of masks. Given the ubiquity of the virus, the low risk of harmful effects, and the probability of benefit on plausible biological grounds, masks should be adopted by the general public even though there is no data to support their use directly.
They say, "Masks are simple, cheap, and potentially effective. We believe that worn both in the home (particularly by the person showing symptoms) and also outside the home in situations where meeting others is likely (for example, shopping, public transport), they could have a substantial impact on transmission with a relatively small impact on social and economic life." Are cloth masks acceptable?
Almost all studies have been conducted with surgical masks: the CDC is recommending ones made of cloth. No trials have been conducted with this particular type of mask, and as such, we have a dearth of verifiable results. However, available data suggest that cloth masks may be only marginally less effective than surgical ones in blocking particle emissions, and are definitely preferable to wearing no mask at all. As the researchers say, "In conclusion, in the face of a pandemic, the search for perfect evidence may be the enemy of good policy."
However, in a related opinion piece , researchers strongly weigh in against allowing healthcare workers at any level to care for COVID-19 patients without donning proper personal protective equipment (PPE), including respiratory protection. In this situation, cloth masks are not an appropriate measure. Source: MacIntyre, R., Chughtai, A., Tham, C. D., et al. (2020). Covid-19: Should cloth masks be used by healthcare workers as a last resort? https://blogs.bmj.com/bmj/2020/04/09/covid-19-should-cloth-masks-be-used-by-healthcare-workers-as-a-last-resort/ Journal references: Greenhalgh, T., Schmid, M. B., Czypionka, T., et al. (2020). Face masks for the public during the covid-19 crisis. BMJ 2020;369:m1435. doi: https://doi.org/10.1136/bmj.m1435 . https://www.bmj.com/content/369/bmj.m1435 Javid, B., Weekes, M. P. and Matheson, N. J. (2020). Covid-19: should the public wear face masks? BMJ 2020;369:m1442. https://doi.org/10.1136/bmj.m1442 . https://www.bmj.com/content/369/bmj.m1442
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