International Journal of Infection Control ORIGINAL ARTICLE Use of cloth masks in the practice of infection control evidence and policy gaps Abrar Ahmad Chughtai?, Holly Seale?, Chandini Raina 1. School of Public Health and Community Medicine, Faculty of Medicine, University of New South Wales, Australia 2. National Centre for Immunization Research and Surveillance of Vaccine Preventable Diseases (NCIRS), The Children's Hospital, Westmead, Australia doi: lO.3396f l C.v9i3.020.13 Abstract Cloth masks are commonly used in low and middle income countries. It is generally believed that the primary purpose of cloth masks is to prevent spread of infections from the wearer. However, historical evidence shows that they have previously been used to protect health care workers (HCWs) from respiratory infections. Currently there is a lack of evidence on the efficacy of cloth masks. In this paper, we examined the evidence around the efficacy of cloth masks and discuss the use of cloth masks as a mode of protection from infections in HCWs. We also reviewed the various approaches implemented to try and improve the effectiveness of cloth masks; for example; type of fabric, masks design and face fit. Our results highlight that there is currently no published research on the efficacy of cloth masks. The few available studies on cloth masks are either descriptive or in?vitro. Studies show that some fabrics may provide better protection than others, and that in?vitro filtration capacity improves with increasing fineness of fabric and number of layers. The presence of moisture, distance traveled by the droplets and the design of mask were identified as other important factors related to the in?vitlo filtration efficacy. Cloth masks may provide some protection and reduce exposure to respiratory aerosols, but this is unproven in the absence of a PCT. Given that cloth masks are widely used around the world and are not adequately addressed in infection control guidelines, research is required to test the clinical efficacy of cloth masks. Other future research questions should include filtration efficacy, length of use, methods of decontamination and fit testing. The use of cloth masks should be addressed in policy documents to inform best practice in low and middle income countries. Keywords: Masks; Infection Control Corresponding Author Dr Abrar Ahmad Chughtai School of Public Health 8: Community Medicine, Level 2, Samuels Building, Faculty of Medicine, University of New South Wales, Sydney 2052, Australia Email: abrar.chughtai@unsw.edu.au Int] Infect Control 2013, v9:i3 Page-l of12 not for citation purposes Use of cloth masks in the practice of IC Ch ughtai et al. Background The use of personal protective equipment is recommended for the prevention of infections in the health care setting."5 Masks and respirators are the most common products referred to in guidelines to prevent the spread of pathogens through the respiratory droplet and aerosol routes?22 The main difference between the two products is their intended use. The described purpose of face masks are to prevent the spread of infections from the wearer and to protect the user from body fluids splashed or sprayed, whereas respirators are used to protect the wearer from others with confirmed or possible respiratory infectioner1 ?3'25 However, in low resource settings, the provision of single?use surgical masks and respirators may not be feasible. Instead, various types of cloth masks (Le. cotton! woven or gauze) are also widely utilized in various healthcare settings in resource?poor countries. In countries such as China and Vietnam, where the historical risk from emerging infections is highEE-E use of cloth masks by health workers (HCWs) is widespread.?30 Currently, there is a lack of sufficient data to either support or refute the effectiveness of cloth masks, in preventing transmission of infections.25 In this article, we examine the historical and present role of cloth masks in the healthcare setting and the evidence regarding the effectiveness of the product. In this setting, we refer to cloth masks as ?reusable masks made of cloth or any other fabric, including cotton, gauze, silk or muslin?. Use of cloth masks in the hospital setting The first evidence of mask use can be traced to the late 19th century, when gauze masks were used by patients to protect the spread of infection.? 33 In 1905, Hamilton proved the presence of Streptococcus in sputum droplets and suggested that HCWs use masks to prevent spread of streptococcus infection in operating theater's.33 It is generally believed that masks were primarily designed to prevent spread of infections from the wearer, i.e. from both patients and HCWs, referred to as ?source control??4 However, the literature shows that masks had also been used to protect HCWs from acquiring respiratory infections in early 20th century. The Institute for Infectious Diseases in Chicago was the first to recommend that masks be used to protect HCWs from respiratory infection. HCWs in Durand Hospital, Chicago used double layered gauze masks from 1913 to 1910,35 which were later changed to triple layered masks in 1919.? Low rates of respiratory infections amongst HCWs were observed after using these masks. Cloth masks were also thought to be effective for preventing secondary transmission of diphtheria and scarlet fever in the patients and HCWs of an Army camp in 1918.35 Cotton masks made up of various layers were used by HCWs and the public during the 1918 Spanish influenza pandemic, however the number of influenza cases continued to rise despite regular mask user? Low perceived effectiveness of the masks used during that pandemic was attributed to the poor quality of masks, inappropriate use of masks.? In comparison, the rate of infection was very low amongst HCWs who used masks made of a half?inch thick cotton pad enclosed by two layers gauze, during the Manchurian Epidemic in 1920?1921 .41 HCWs have also been documented with using pillow slips and celluloid to make masks during the 1 924 epidemic of plague in Los Angeles? The use of cloth and gauze masks continued during the 1930?s and 40?s by nurses for the prevention ofTEan5 These masks continued to be recommended for use during the 19505 and 19605, even though by then a few disposable masks had been introduced into the market.? The extent to which cloth masks are currently being used in the low and middle?income countries is impossible to gauge, as the data currently available are limited. However, based on anecdotal information, it is believed that the practice is widespread in Asia, for example in China and Vietnam?a'? Furthermore, there were reports that cotton masks were used by HCWs during the SARS outbreak in ChinaFgr?? In the initial phase of the SARS outbreak in Vietnam, approximately of HCWs wore a cloth orsur?gical masks, however, after the first week there was 100% N95 respirator use.43 However, in many of these settings, from our experience of conducting clinical research, a wide range of unproven practices occur, including double? masking, extended or reuse of masks and washing of masks using various different techniques. There is little evidence of cloth mask use in high income countries, however some researcher have recommended the use of cloth masks in case of adverse effects during the long use of In addition to that some regional pandemic influenza plans discuss the use Int] Infect Control 2013, v9:i3 doi: Page 2 of 13'. not for citation purposes Use of cloth masks in the practice of IC Ch ughtai et af. of cloth masks in certain situations. For example; in California, Sonoma County Department of Health Services developed plan for pandemic influenza and recommended cotton masks in the event of a shortage of N95 respirators and surgical masks.31 Effectiveness of cloth masks The first study on cloth masks was published by Weaver in 1918.35 He examined the rate of diphtheria and scarlet fever among the nurses before and after the use of two layered gauze masks. He reported a significant reduction in the incidence of diphtheria {23.5% to and scarlet fever to amongst the nurses. In a second study, he tested masks in a controlled environment, which had been made up with various layers and reported an improvement in the effectiveness of gauze mas ks associated with increasing fineness of the cloth and the number of layers.31 In 1959, Shooter and colleagues evaluated three types of masks to prevent the spread of staphylococci from the wearer. They compared a four layer cotton mask, with a mask made from two layers of woven cambric with a piece of paper in between and a paper mask surrounded by cellulose wadding. All three masks were found effective in preventing spread of staphylococcal infection.52 A couple of years later, Greene and Vesley evaluated a two layer gauze mask and found that it was effective in blocking particles greater than 4 um and less than 4 urn Lastly in 19?5, Quesnel assessed various types of surgical and cotton masks and concluded that well designed cotton masks may be effective in preventing infection.? During the middle of the 20th century, the focus of research around mask use was to protect HCWs from tuberculosis (TB). McNett developed a series of masks and checked their effectiveness by estimating the rate of infection among the nurses. A 50% reduction in the prevalence of TB was observed amongst nurses who used the 6 layer cloth mask.44 Cloth masks were also found effective in protecting rabbits against the inhalation of tubercle bacilli.? Since the development of surgical masks and respirators, very little research has been conducted on cloth masks recently. To our knowledge, only three studies were done on cloth masks during the 215t century, and all in a laboratory setting. Dato and colleagues tested a handmade mask, made from cotton T?shirt material, for fit testing and filtration. After introducing the challenge aerosol, substantial protection and good fit were reported.54 In the 2?:l study, Sandy and colleagues studied respirators, surgical and cloth masks and concluded that all three products provide respiratory protection to a degree, with respirators providing the maximum protection and homemade cloth masks the minimum.55 Lastly, Rengasamy and colleagues tested the filtration performance of various types of cloth masks and concluded that respiratory protection is minimal by cloth masks but that certain types of cloth fabric may have more protective value than others.? Three factors were highlighted in these studies in regards to the filtration capacity of a cloth mask: 1) closeness of the gauzefcloth threads; 2} number of gauzer?cloth layers and 3) type of gauzer?cloth. Generally, the filtration capacity improved when the number of threads increased in the gauze and the mesh become finer compared to course gauze with lower thread counts?lrf?'j? Similarly, the number of layers was found to be directly proportional to the filtration capacity in most of the laboratory studies. In these studies, the filtration effectiveness significantly improved with increasing the number of layers in the mask?id?-E??g Certain types of cloth provides better protection than other; e.g. fine muslin (loosely?woven cotton fabric) was better than the gauze,58 gauze padded with cotton were better than simple gauze or paper masks?(30 and towels were more effective than other fabrics?? Cloths masks were generally found to be effective against large particles however some evidence exists against small particles as well.? Presence of moisture, distance traveled by the droplets and the design of mask were some other factors affecting the filtration capacity. In summary, the filtration capacity of wet masks has been reported as being lower compared to dry masks.?EU The distance traveled by the droplets is associated with the filtration capacity and filtration capacity is generally decreased by decreasing distance.? 51 Finally, the design of a mask is also important and some designs are more effective than others, particularly those with a tight seal around the There are many limitations in the available research around cloth masks. most of the studies were conducted in first half of the 20th century. After the Int] Infect Control 2013, v9:i3 doi: IUJEQEEIJICNQIEDZUJ3 Page 3 of I 2 not for citation purposes Use of cloth masks in the practice of IC Ch ughtai et at. development of disposable surgical masks in the 1960?s, very few studies have been conducted on cloth masks, and to date there have been no randomized, controlled clinical trials of cloth masks. Recently published RCTs and other studies have focused only on surgical masks and respirators.? 53'? Secondly, most of the studies on the use of these products have been in laboratory settings, using bio?aerosols and manikins??rSE-Siel?a Thirdly, extended use and re?use of cloth mask have not been discussed in much detail in the literature. Extended use refers to ?using a mask or respirator by the same wearer for a prolong time?. Staff may continue to use the same mask over a period of time without removing it or may don/doff the mask between patients. A recent survey in Vietnam revealed that HCWs use masks for varied of time.? Reuse after decontamination refers to the mask being reused over multiple dayslweeksfmonths by either the same or different HCW. Cloth masks are typically washed or decontaminated between uses. Various decontaminated methods have been documented, for example; autoclave, isopropyl alcohol, bleach, hydrogen per oxide, microwave, soap and water, ultraviolet radiation and dry heat?5 While, the material of cloth masks is unlikely to degrade with standard means of disinfection Ie.g., chemicals, heat, and radiation), unlike other types of disposable facemasks or respirators, there is currently little evidence about the effectiveness of these decontamination methods. As a result of these laboratory studies, the use of cloth masks was recommended for particularly during epidemics and pandemics in the early 19th century.??42 Therefore, whilst these studies were only conducted to examine the spread of infections from the wearer, the same studies were also used to justify the use of masks in preventing infection for chs?sazss During the pandemic of influenza in 1918, authorities quoted the same studies in order to implement compulsory use of mask in the hospitals and public places?m Policies and guidelines around the use of cloth masks in health care setting Reference to or recommendations around the use cloth masks are currently not made in any publically available gu idel ines regarding the use of PPE for routine care to protect against respiratory virus transmission. A review of publically available pandemic influenza policy documents reveals that none of the guidelines mention the use of cloth masks?? However, the use of cloth masks has been discussed for other infective diseases. In cases of non?availability of surgical masks, CDC recommends using cotton masks made from four or five layers of cotton cloth for infection control of viral hemorrhagic fevers in the African health care setting.? The WHO discouraged masks use in the community setting during influenza A outbreaks due to lack of evidence, however, the option of use and reuse of various types of cloth masks is discussed. In case of cotton masks, WHO advises washing cloth masks with house hold detergent after use"2 The use of cloth masks during an extended outbreak or pandemic According to a CDC estimate, approximately 1.5 billion masks and 90 million respirators would be needed by the health sector and around 1.1 billion masks would be needed by the public for a six week influenza pandemic.25 For most low income countries, it is highly unlikely that they will be able to provide disposable masks, let alone respirators forthat extended period of time and may have to ration the use of these products. During an extended outbreak or influenza pandemic, the use of cloth masks may be the only option available in low resource settings. In a survey conducted in Japan during the SARS outbreak, around 40% HCWs agreed that gauze masks may be used to protect from Recently, the high demand for masks and the potential reliance on cloth masks during an influenza pandemic, was acknowledged by the Institute of Medicine (10M) when preparing their report on the reusability of facemasks. The committee members did not advise against the use of cloth masks, however they recommended further research be undertaken on the use of cloth masks, including commonly used fabrics like T?shirts, handkerchiefs and scarves.23 One of the issues is that the quality and nature of cloth masks used around the world are varied and not subject to any regulation. Currently, only N95 respirators are subject to regulation around filtration capacity. It is currently not clear whether the wide range of cloth masks or improvised masks can meet the standards set by regulatory bodies.25 Interestingly, it should be noted that surgical masks are similarly not subject to any regulation, and face the same issue. Int] Infect Control 2013, v9:13 doi: Page 4 of 13'. not for citation purposes Use of cloth masks in the practice of IC Ch ughtai et ai. There is currently a concern that cloth mask use may give users a false sense of protection in the absence of proven efficacy that will encourage risk taking andfor decrease attention to other hygiene measureSFS'EE Conclusion Although cloth masks are commonly used in low? middle income countries, there is minimal policy acknowledgment of the need for cloth masks, and a lack of evidence on their efficacy and use. Cloth masks are generally not mentioned in any policies on the use of PPE during an influenza pandemic. The lack of recommendations for respiratory protection may be due to a lack of evidence on their efficacy. Despite the lack of evidence and the little attention paid to cloth masks in guidelines and policies, they continue to be widely used around the world, particularly in resource?poor countries. In many settings, the high cost of masks and respirators (around per surgical mask and per N95 respirator for products manufactured by a leading company) is probably one of the main factors inhibiting the regular use of these products. More concerning is the fact that cloth masks are widely used in countries which have been historically important for the emergence of new infections such as China and Vietnam. There is an urgent need for research to quantify the efficacy of cloth masks with a RCT, and to study the various associated practices such as re?use and sterilization techniques globally. 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Int] Infect Control 2013, v9:i3 doi: Page 2' of 12 not for citation purposes not for citation purposes Int] Infect Control 2013, v9:i3 doi: 10.3396?le.v9i3.020.13 Page 3 of12 Table Studies on cloth masks Authorsf year of study Type of study Focus of the study (Protect wearer or protect spread to others) Methodology Type of material tested Main findings Weaver 191835 Observational Protect HCWs from infections Rates of diphtheria and scarlet fever were compared in the HCWs in two periods; i.e. before and after use of masks Two layered gauze mask Low rate of diphtheria and scarlet fever observed in HCWs after using masks Capps 19183'3 Observational Prevent spread of infection from wearer and protect wearer from infections Face masks were used by the HCWs and patients in Camp Grant and upon success of the experiment, mask use was started in all medical wards Cloth masks The secondary transmission of scarlet fever and measles was reduced in the wards by using the masks Haller191859 Laboratory Prevent spread of infection from wearer Patients coughed on the petri dishes covered by various gauze masks. Then experiment was revised with double masks, i.e. one on perti dish and one on patients mouth. Numbers of colonies were counted. Gauze masks of various types The number of colonies depends on the type of gauze and number of layer. Doust 191857 Laboratory Prevent spread of infection from wearer Agar pates were placed in front of study subjects, while they spoke, talked and coughed with and without gauze masks. Bacillus prodigiosus was used to test various masks. Two to ten layers of masks made from coarse gauze, medium gauze, and butter cloth Three layer butter cloth masks, made of fine gauze, were found to be more effective in preventing spread of infection Leete 191958 Laboratory Prevent spread of infection from wearer The emulsion of staphylococcus was sprayed on the petri dishes covered by gauzes of various types and layers Dry and wet ordinary surgical gauzes, fine muslin 6 to 8 layer fine muslin provide better protection than then the gauze masks Dry masks are better than the wet masks Use of cloth masks in the practice of IC Ch ughtai et at. not for citation purposes Page 9 of12 Int] Infect Control 2013, v9:i3 doi: 10.3396?le.v9i3.020.13 Weaver 1919? Laboratory Prevent spread of infection l' Bacillus prodigiosus (in NaCl solution} was sprayed into the petri dish, through an opening in a cardboard by a hand atomizer. Various types of gauzes were placed onto the opening. The experiment was then repeated with a patient with respiratory infection. The number of colonies in the petri dish (containing nutrient and blood agar) was measured. Gauze masks of various types and layers were used The number of colonies in the dishes was decreased by increasing the distance of spray from opening, increasing fineness and number of layer of cloth Kellogg 19204? Observational Prevent spread of infection and from wearer and protect Laboratory wearer from infections Report of State Health Officials on the use of masks in California, during the during the influenza outbreak in 1919 If followed by a series of laboratory tests Gauze masks Certain types of mas ks may be effective, (depend on type of cloth and number of layers}, however its use should not be compulsory. The leakage around the face increases when thin layer of gauze use. Observations Prevent spread ofinfection and from wearer Laboratory Survey in 100 hospitals, 60 hospitals responded, 42 sent masks sample. Masks were worn by student volunteers who were carriers of streptococcus and petri dishes were placed in front of them. The number of colonies were counted at the end. Various types of mas ks tested, including a 10 inch gauze mask of two layers, with 6 inch rubber in between. Of 42 masks, only masks were of good quality. None of them was germ?proof in testing. Gauze mask with rubber in the center was considered germ proof. Use of cloth masks in the practice of IC Ch ughtai et at. not for citation purposes PagelOoflE Int] Infect Control 2013, v9:i3 doi: Blatt 1933'31 Laboratory obselvati onal Prevent spread of infection from wearer and protect wearer from infections A dust?proof tunnel was constructed. Two nurses with respiratory infection were given various masks and asked to cough in the champers. Petri dishes were placed in the champers at various distances and colonies were counted later. New mask use was observed in nurses Various types of commonly used masked and a newly made cellophane gauze mask. Simple 6 layer gauze masks were not effective. Newly macle cellophane gauze masks were effective and comfortable to wear. Paine 193562 Laboratory Prevent spread of infection from wearer Tested the penetration of the high momentum droplet through various fibers. An apparatus, similar to the shape of face was used, with three holes representing the nares and mouth. Atomizer charged with a broth culture of Micrococcus lysodeikticus were sprayed. The colonies were counted on nutrient agar. Silk, surgical gauze and dental gauze Two layer of silk, eight double layers of surgical gauze and four layers of dental gauze are effective in reducing the droplet penetration. The design of mask is important. McKhann 9385? Laboratory Prevent spread of infection from wearer Bacteria were sprayed in the petri dishes covered by the various masks. The numbers of colonies were counted. Gauze mask, impervious mask, paper masks and a new type of filter mask {cotton layers between the gauzes) New type of filter mas ks were most effective. Paper masks were not effective as they become wet very quickly. McNett 194944 Observation Protect wearer from infections Developed series of masks and checked their efficacy by various means, including rate of infection among the nurses. Various types and layers of cloth masks 50% reduction in the prevalence of TB was observed in the nurses after using 6 layer cloth masks Use of cloth masks in the practice of IC Ch ughtai et at. not for citation purposes Pagell oflE Int] Infect Control 2013, v9:i3 doi: Lurie 19494159 in laboratory Animal testing Protect wearer from infections Bovine TB bacilli were nebulized into a chamber and faces of rabbits were exposed to the TB bacillus. Masked and unmasked rabbits inhaled in the chamber and tuberculin tests were performed to see the rate of infection. 3 to 6 layer of gauze masks 4 to 6 layer gauze masks effectively filter 90 to 95 of the bacillus. Wearing masks was recommended. Shooter 1 95952 Laboratory Prevent spread of infection from wearer Evaluated three types of masks to prevent the spread of staphylococcus from the volunteer?s month. A chamber was made with help of a table and canopy. Volunteers used three types of masks and the number of colonies were counted on the blood agar in the petri dishes placed in the chamber Four layer cotton mask, double layer woven cambric with a piece of paper in between, a paper mask with outer and inner layer of paper with cellulose wadding between All masks were found effective in preventing spread of staphylococcus infection Greene and Vesley 196253 Laboratory Prevent spread of infection from wearer Used a specially designed chamber to collect air sample. Study subject breathed into the chamber with and without mask and the number of oral bacteria were counted on blood agar Masks made of two layers of fine muslin Masks were effective mainly against the large particle i.e. greater than 4 um Quesnel Laboratory Prevent spread of infection from wearer Tested five masks of various types and design. Testing chamber used to collect contaminated particles through the mask and around the masks Four layer cotton masks, various types of surgical masks made of polyester and rayon fibers All masks were effective against large particles; however three of them were more effective against the small particles. Results of well designed cotton masks are comparable to the fiber masks. Use of cloth masks in the practice of IC Ch ughtai et af. not for citation purposes Pagel? of12 Int] Infect Control 2013, v9:i3 doi: Dato 200654 Laboratory Prevent spread of infection from wearer Cloth mask was used on the panel faces and challenge agent was measured inside and outside the mask with Portacou nt Plus Respirator fit tester with N95 Companion Cotton {heavywe ight T?shirts) of various layers Handmade masks can provide good fit and reasonable protection. Sande 200855 Laboratory Protect wearer from infections Healthy volunteers wore respirators and various masks. Protection factor was measured with fixing receptors insides and outside the masks to count free particles. Portacount was used to count the particles. Compared respirator, surgical mask and homemade cloth mask All masks provide some protection, however respirator provide maximum protection, followed by surgical masks and then homemade cloth masks Rengasamy and col leagues 2010?3 Laboratory Protect wearer from infections Tested the filtration performance of various types of cloth masks against the polydisperse and monodisperse aerosol particle in the 20?1000 nm range. TSI 8130 Automated Filter Tester (TSI 8130} was used for test. Various types of fabrics were tested, including sweatshirts, T?shirts, towels, scarves, and cloth masks The respiratory protection is minimal by cloth masks and certain type of cloth fabric may impart more protective value than others. Use of cloth masks in the practice of IC Ch ughtai et at.