key: cord-258859-iaiosjlu authors: Wang, Jiao; Pan, Lijun; Tang, Song; Ji, John S.; Shi, Xiaoming title: Mask use during COVID-19: A risk adjusted strategy() date: 2020-06-25 journal: Environ Pollut DOI: 10.1016/j.envpol.2020.115099 sha: doc_id: 258859 cord_uid: iaiosjlu In the context of Coronavirus Disease (2019) (COVID-19) cases globally, there is a lack of consensus across cultures on whether wearing face masks is an effective physical intervention against disease transmission. This study 1) illustrates transmission routes of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2); 2) addresses controversies surrounding the mask from perspectives of attitude, effectiveness, and necessity of wearing the mask with evidence that the use of mask would effectively interrupt the transmission of infectious diseases in both hospital settings and community settings; and 3) provides suggestion that the public should wear the mask during COVID-19 pandemic according to local context. To achieve this goal, government should establish a risk adjusted strategy of mask use to scientifically publicize the use of masks, guarantee sufficient supply of masks, and cooperate for reducing health resources inequities. globally, countries have utilized precautionary measures against this pandemic. However, 30 there is a lack of consensus across cultures on whether wearing face masks is an effective 31 physical intervention against disease transmission. This study aims to illustrate 32 transmission routes of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-33 2), address the controversies surrounding mask wearing, and provides suggestions for the 34 use of facial masks during the COVID-19 pandemic. 35 The references search was conducted on March 11, using three databases (PubMed, 36 CNKI, and Web of Science) with the search terms "COVID-19", "2019-nCoV", "novel 37 coronavirus", or "SARS-CoV-2" and "mask", "facial mask", or "face mask". The team 38 members individually assessed the relevance and validity of each study. Non-peer 39 reviewed manuscripts from preprint servers were not considered. We also searched the Another important feature of the COVID-19 is that asymptomatic cases proportion 86 is high. It is estimated approximately 60% of all infections convert from cases with mild 87 symptom or asymptotic cases and might be passing the virus on to others (Qiu, 2020 However, global spread of SARS-CoV-2 is far greater than MERS and SARS, which 107 might be associated with cases with mild symptom or asymptomatic cases. According to 108 Wrapp et al., the binding of SARS-CoV-2 to the obligate receptor of Angiotensin 109 Converting Enzyme 2 (ACE2) is of higher affinity than that of SARS-CoV (Wrapp et al., 110 2020) , indicating that those with medical comorbidities may be at higher risks. This may 111 also indicate a higher time to infection, even in the absence of masks (Pung et al., 2020) . avian influenza, influenza, and haze events. Hence, wearing masks has become a 154 pervasive in society as a way to prevent exposure. This is for good reason, as the 155 population density in Asian countries is generally higher than that in western countries, 156 and the crowding in a confined place will increase the infection risk or exposure. 157 Therefore, during the COVID-19 pandemic, the public is encouraged to wear masks in 158 public places and people often comply as a form of health-seeking behavior (Greenhalgh 159 et al., 2020) . 160 However, in many western advanced economies, those wearing masks are often met 161 with suspicion in public, even causing panic in certain situation. Universal mask use in 162 the community has been discouraged by some health authorities with the argument that 163 masks provide no effective protection against coronavirus infection (Feng et al., 2020) . effectiveness studies is mainly due to different study contents, study designs, evaluation 177 methods and endpoints. Understandably, good evidence on this topic is difficult to assess. 178 Many studies used self-reported questionnaire to quantify mask uptake status, which may 179 introduce subjective bias because the description depends on perception of participants 180 Suppose if only symptomatic cases wore masks, we would miss those asymptomatic 261 cases, which increases the possibility of spreading the virus before realization that they 262 carry the virus. However, we should note that requiring the general public to wear masks 263 would put high pressure on mask supply, and insufficient guidance would even trigger a 264 run on medical protection products creating a lack of PPE for medical professionals. 265 Therefore, scientific strategy and strategic guidance should be established, and enough 266 mask supply should be guaranteed under the frame of inter-or intra-national cooperation. 267 268 As Tedros Adhanom Ghebreyesus, the WHO Director-General, mentioned on 270 March 18, 2020, "do not assume you will not be infected, prepare as if you will die" 271 (Ghebreyesus, 2020) . The Government of China has implemented a risk-based mask use 272 strategy for general public, people in public congregated places and confined congregated 273 places, confirmed/suspected cases and close contacts, and occupational exposed workers 274 under various scenarios, which could be used as a reference ( Table 1) . As an example, 275 during the COVID-19 pandemic, it is suggested to wear the mask in congregated places 276 such as offices, shopping malls, restaurants, conference room, etc. or relatively confined 277 environments such as elevators, transportation vehicles, etc. The mask is generally used 278 by general public, while the respirator or a filtering face piece, which is designed to 279 protect the wearer from exposure to airborne contaminants, is mainly used by health care 280 workers especially during AGP (European Centre for Disease Prevention and Control, 281 2020). The exhalation valve is sometime used in the respirator in order to reduce the 282 breathing resistance. However, the inhalation valve closes and the exhalation valve opens 283 of the mask when the wearer breathing, implying that the exhaled gas is not filtered and 284 directly discharged into the surrounding environment. As a result, the respirator 285 recommended for suspected cases, confirmed cases, asymptomatic carriers, and close 286 contacts must not contain the valve (CDC, 2020c). Moreover, considering the probable 287 insufficient mask production, masks could be repeatedly used under the prerequisite of 288 public health protection in areas with middle to low risks. 289 There is not a single measure that could provide complete protection to the public. 300 Therefore, mask use must be combined with hand hygiene, ventilation improvement, 301 reduction of gatherings, and social and physical distancing. To inform the public, the 302 government could 1) invite mainstream press such as TV stations, broadcasts, 303 newspapers, etc. to participate in mask education; 2) spread relevant knowledge via social 304 media (e.g. Twitter, Facebook, and Instagram) or display screens and billboards in public 305 places; 3) hand out mask instruction materials to the public; and 4) carry out training and 306 seminars in places such as hospitals, schools, kindergartens. 307 308 As the use of masks during the COVID-19 pandemic would contribute to the rapid 310 consumption of masks in limited time, two essential countermeasures should be taken 311 into consideration. The government should timely stimulate mask production. Many 312 countries have been facing a severe shortage of medical resources, including medical 313 masks. In this circumstance, the mask price increased sharply, and the public stole or 314 fought for masks in some regions; in addition, diplomatic disputes even arose. To solve 315 this problem, the government could 1) procure surgical masks globally through different 316 channels and means; 2) distribute masks in accordance with risk level; and 3) explore 317 prospects of local production. Research on mask reuse should also be encouraged. For 318 example, Song et al. has proposed an approach for medical mask use using hairdryer, and 319 they are still working on further improvement . After the treatment, the 320 medical mask could be used by the public, but the reuse in a hospital settings is still 321 unexplored. 322 323 The face mask distribution priority should be given to healthcare workers providing 326 care services (e.g. front-line healthcare workers, nursing staff in institutions, and 327 healthcare personnel in private clinics); personnel who provide essential services and 328 who are required to have contact with the public at work (e.g. those providing public 329 transport, emergency services and immigration services); and vulnerable groups in the 330 society (e.g. unaccompanied children, elderly people without family support, and 331 disabled persons). 332 The globe is more interconnected than ever; if the countries with weaker health 333 systems fail to control the pandemic, other countries would be re-exposed by the COVID-334 19 for the foreseeable future. If the countries with weak health systems fail to control the 335 pandemic, other countries would be exposed in the danger of being harassed by the 336 COVID-19 for the long term. As chief of U.N. claimed, "We must create the conditions 337 and mobilize the resources necessary to ensure that developing countries have equal 338 opportunities to respond to this crisis in their communities and economies" (United 339 Nations Secretary-General, 2020). In mid-February, France took early action to help 340 China, sending 17 tons of similar supplies. Under the well control of COVID-19, China 341 has sent supplies to Italy, the hardest hit among European countries, and to Spain (US 342 News, 2020a). Case in point, LVMH, the world's biggest luxury goods group, has also 343 ordered 40 million health masks from a Chinese supplier to help France coping with this 344 pandemic (US News, 2020b). It could be seen that international cooperation, with 345 manufacturing and distribution logistics may optimize mask resource allocation. 346 In each country, the most vulnerable group should be paid more attention when In the context of rapid spread of COVID-19 globally, there is a lack of consensus on 361 the mask use as a NPI amide the pandemic. This study summarized that: 1) main 362 transmission routes of SARS-CoV-2 include droplet, contact transmissions, and possible 363 airborne transmissions, which is characterized by high proportion of cases with mild 364 symptom or asymptomatic cases, strong infectivity, and a large number of clusters; 2) 365 The necessity of wearing masks by the public during COVID-19 pandemic has been 366 under-emphasized; and 3) A risk basis mask use strategies and compliance improvement 367 are suggested. 368 369 JW and XS had the idea for and designed the study. JW and LP drafted the paper, and all 371 authors critically revised the manuscript for important content and gave final approval for 372 the version to be published. All authors agree to be accountable for all aspects of the 373 work in ensuring that questions related to any part of the work are appropriately 374 investigated and resolved. JW and LP contributed equally to this work. 375 We declare no competing interests. 377 The authors would like to acknowledge all health-care workers involved in the diagnosis 379 and treatment of patients during the pandemic in the globe. 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