All about the mask with covid19
  • Yuni Kim
  • Updated 2020.05.04 20:42
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People wait in line to buy a mask for 1000 KRW (0.62 USD) at a “National At Cost Mask Sale” on March 2, 2020. ⓒSisaIN Seon-young Shin

Masks are the symbol of pandemics. On March 7, USA Today released an excerpt from a diary 102 years ago. “It says in to-night’s paper that to-morrow all Seattle will be wearing masks. No one will be allowed on a streetcar without one,” wrote Violet Harris, a 15-year old living in Seattle, WA, USA in October 1918. An influenza virus (H1N1), the so-called Spanish Influenza, was terrorizing the whole world. Harris’s father was to buy masks for the family, but could only find three out of the needed seven. From the time of the spreading of this notorious virus that killed at least 25 million people worldwide, masks were at the front line of epidemic prevention.

Masks are another name for anxiety for people living in the age of COVID-19. Unstable supply and demand caused a “mask crisis,” and the government’s recommendations inadvertently created more confusion. While the Korean Ministry of Food and Drug Safety suggested that one wears KF94 or better (N95 or FFP2) masks in February, they expanded their recommendation to include KF80 (FFP1) or even cotton masks in March. The World Health Organization (WHO) or the American Center for Disease Control (CDC) even went so far as to recommend that healthy people do not need to wear masks as long as they are not taking care of the (suspected) infected. Experts do not agree on the matter. Whose words should one trust?

Behind masks, no bigger than an adult’s palm, many stories hide. One must consider the uncertainty inherent in masks, the insufficiency of information on COVID-19, and the positions of the individual and the group. Such complexities result in a perfect storm that is the mask acquisition.  

■ Masks, the Uncertainty that are

Professor YOON Chungsik (Seoul National University Graduate School of Public Health), an expert of environmental health, conducted several mask-related research projects in South Korea. Yoon first explained why it is difficult for experts to speak with certainty on wearing masks for the prevention of COVID-19. “We know quite a lot about viruses already. We are also very much knowledgeable about mask performance in terms of collection efficiency. But when it comes to coronavirus 2, the virus behind COVID-19, the story changes.”

Coronavirus 2, which causes COVID-19, is a novel virus. Experts are in the process of developing precise knowledge on coronavirus 2 — most of what we know is inferred from existing literature on coronaviruses. Many pieces remain in the dark. Most importantly, the modes of transmission are unclear. It is difficult to put the function of masks in definite terms. Salt particles and oil droplets are used to test mask performance. Estimates are then made on the effectiveness of virus and germ protection.    There has been research regarding respiratory infections. Many are to examine the effectiveness of surgical masks or N95 (or KF94, in the case of Korea) masks for health professionals. Scholars agree on the effectiveness of masks in preventing infections in the case of healthcare professionals in contact with patients. It is worth perusing WHO’s publication on the “Non-pharmaceutical Public Health Measures for Mitigating the Risk and Impact of Epidemic and Pandemic Influenza.” Influenza is what we commonly call the flu. In this report, WHO performed a meta-analysis of ten studies (Total N: 6000) on the effectiveness of masks for the community-based general public rather than for health facility-based personnel. The study showed that should one wash hands and wear masks, the chances of infection decrease by 22 percent, whereas should one only wear masks, the chances decrease by 8 percent.   This does not mean that the masks were proven effective. The confidence level of this analysis includes “no difference,” which does not disprove the hypothesis that “there is no preventative effect.” WHO also considered this in stating that there is a lack of sufficient evidence on mask effectiveness. Nonetheless, the report concludes that one should wear masks when exhibiting symptoms, and the general public should wear masks for self protection limited to times of serious epidemics. Although there is no evidence, there is a high expectation of effectiveness based on theory. Many other non-pharmaceutical measures were also considered, and “handwashing” was recommended without a doubt.   

■ The Varied World of Masks

Masks can be categorized into winter face masks, surgical masks, and respirators. Winter face masks, more commonly known as cloth or cotton masks, are not subject to approvals. Surgical masks or dental masks require the approval of the Ministry of Food and Drug Safety. Surgical masks’ particulate filters, at sizes 2 to 10 micrometers (㎛), are bigger than respirators’. ㎛ is a very small measurement, one ten-thousandth of 1 cm. Respirators are designed to protect wearers in industrial settings, and are commonly referred to as dust masks as they are protections against fine dust and yellow dust. The filter penetration limit of respirators are tested using salt particles (0.6 micrometers) and oil particles (0.4 micrometers). Only when the filter penetration limit exceeds 80%, 94%, and 99% respectively does the Ministry of Food and Drug Safety certify them as KF80, KF94, and KF99. (Class KF80 masks are tested only using salt particles.)

Data: YOON Chungsik (SNU Graduate School of Public Health)

The discussion on mask effectivity concentrates on respirators. Respirators consist of several layers of nonwoven mechanical filters. A particular company may use from three up to seven layers. Electrostatic filters refer to electrically charged layers of nonwoven filters. Multiple layers of nonwoven filters are required to filter solely through mechanical interception. From the mid-1990s, an electrostatic charge has been used to further mask effectiveness. The fact that the radius of the mask filter is at 0.4-0.6 ㎛ does not mean that smaller particles simply pass the filter. Mask filters have a variety of operation mechanisms that prevent smaller particles from reaching the wearer’s mouth and nose. Masks are less effective, however, against particles of sizes 0.2-0.3 ㎛. (Refer to 〈Picture 3〉)

The idea that the masks are less effective once wet is due to electrostatic filters. Yoon states, “Electrostatic filters contribute 20-30% to mask performance. When workers wear masks for eight hours a day at work stations, moisture does not immediately deteriorate mask performance.”  

■ The World of COVID-19

How does the COVID-19 spread from the infected to the uninfected? Questions on mask performance can only be answered after answering the first question. The virus behind COVID-19 spreads through saliva (respiratory droplets). A great amount of saliva comes out when one coughs or sneezes. Cough etiquette, such as covering one’s cough with an elbow, is hence critical. Small droplets also come out when talking. Contact transmission is the main transmission pathway for COVID-19. The saliva of the infected lands on surfaces such as door handles. The saliva then makes its way to another person’s hand. It enters the person’s respiratory system when he or she rubs her eyes or touches his or her mouth. That is why handwashing is being emphasized everywhere.    Masks are meant to prevent respiratory and aerosol transmission. Experts do not dismiss the possibility of aerosol transmission for COVID-19 but see it as unlikely. The dictionary definition of aerosol is fine solid or liquid droplets of radii 0.0001-100 ㎛. As it is commonly used today, aerosol refers to small saliva droplets under 5 ㎛. Saliva droplets of such a size may be transmitted air-borne, instead of falling to the floor within 1 m. Bigger saliva droplets are called respiratory droplets.   The entry of a single virus into the body does not mean infection. Although dependent on the virus, 1000 to 10,000 viruses must enter the body to cause minimal infection. The size of the COVID-19 virus is 0.12-0.14 ㎛, four times bigger than the rhinovirus that causes the common cold. Its size signifies a precipitous fall of virus density in aerosol droplets. Of course, density is not the only factor that affects transmission. Epidemiological studies suggest that the transmissibility of COVID-19 virus is quite high. Nonetheless, it would be a stretch of imagination to think that the scary virus is flying through the air all over the place. Professor JOO Chul-hyun states, “all viruses lose transmissibility once they leave the human body. Coronavirus, especially, seems to lose transmissibility without moisture.”

Morning Rush Hour in Central London, March 18 ⓒAFP PHOTO

■ To wear or not to wear a mask

The Korean Ministry of Food and Drug Safety, the World Health Organization, and the American Center for Disease Control all dispense the following information on masks. Anybody exhibiting symptoms such as coughs or sneezes should wear a mask. The most fundamental and the most critical role of masks in public health is to prevent the infection of others. Questions remain, however. COVID-19 shows a high viral load close to the onset of symptoms— asymptomatic virus shedding — and cases of asymptomatic infections. If the general public do not wear masks as per WHO and the American CDC guidelines, are they not exposed without protection to those infected without or with only mild symptoms?   On March 3, Hong Kong-based researchers contributed “Mass masking in the COVID-19 epidemic: people need guidance” (correspondence article) to the Lancet that took account of asymptomatic virus shedding and infections: “WHO recommends against wearing masks in community settings because of lack of evidence. However, absence of evidence of effectiveness should not be equated to evidence of ineffectiveness, especially when facing a novel situation with limited alternative options.”

A streetcar conductor in Seattle in 1918 (during Spanish Flu) refusing to allow passengers aboard who were not wearing masks. Spanish Flu, ⓒWikipedia

Then, which masks should one wear? Experts agree that despite some controversies, it would be helpful to wear any, whichever one. Professor KIM Hong-bin (Internal Medicine Infectology) at the Seoul National University Hospital Bundang advises to adhere to common sense when considering masks: “the primary purpose of masks is to prevent spitting when coughing or talking. Whichever type of mask, it has interception capabilities compared to not wearing one.” There is no need, however, to wear a mask when alone — like when driving — or in less crowded parks and streets. Professor NAM Jae-hwan (Bioengineering) at Catholic University states, “there is an extremely low possibility of infection through the infected breathing while passing next to the uninfected in open air.”  

The Korean Ministry of Food and Drug Safety suggests that one wear KF94 when attending patients with suspected COVID-19, KF80 or above when the general public are visiting health facilities, exhibiting respiratory symptoms such as coughs or runny nose, or when the people who are at higher risk must make contact with others within 2 meters in poorly ventilated spaces. The Ministry advises that cloth (cotton) masks are helpful when there is a low risk of infection. 

Data: YOON Chungsik (SNU Graduate School of Public Health)

■ The Reason for Differing Mask Guidelines

Each country also provides differing guidelines on mask reusals. WHO discourages reusing single-use masks. The Korean Ministry of Food and Drug Safety lays down single use as the principle for respirators, but also informs that the same wearer may reuse the mask if it has been worn temporarily in a low-risk environment. The mask should be kept at a well-ventilated, clean location. In Taiwan, where one can buy three masks per week in a rationing system akin to Korea’s, the official guideline is that masks can be worn twice or thrice.   While East Asian countries widely recommend wearing masks, the West has been reluctant to recommend masks unless in specific circumstances. There may be cultural differences, but also other factors may play a role. People may comparatively disregard more important rules of personal hygiene, such as handwashing, when wearing masks. Risks of infection may even be higher when one does not know how to properly wear a mask. The Korean Ministry of Food and Drug Safety and the World Health Organization advises how to properly wear a mask on their respective websites.    The second factor has to do with the supply and demand of the masks. European and Northamerican countries are ill-equipped with production capabilities to match the explosive spike in demands. 50% of the world’s masks are produced in China. China, which used to produce 20 million masks daily on average, now increased their production capabilities to 110 million masks daily. Korea, too, ranks in the top 5 countries when it comes to mask production. On January 30, 6.59 million respirators were produced. After the spread of COVID-19, Korean mask companies have extensively increased their production capabilities to 10 million masks daily. From the 2000s, wearing respirators against the annual yellow dust and the constant fine dust threats became the norm. The number of products approved by the Ministry of Food and Drug Safety increased rapidly. In this process, the domestic mask industry developed immensely.  

Data: “Characteristics of Health Masks Certified by the Ministry of Food and Drug Safety” (HAHM Seunghon and 3 others, Gachon University Medical School Occupational Environment Medicine. 2019)

  The WHO’s discouragement of masks for the general public, and the European and Northamerican countries’ limitation of respirators to the use of medical staff reflect each country’s situation. On March 3, the WHO warned that the lack of personal protective equipment (PPE) is endangering health professionals worldwide. Personal protective equipment includes surgical masks and respirators. According to the WHO, after the surge of COVID-19, the price of surgical masks has increased six-fold, and that of N95 respirators has doubled. To match the increasing demand, PPE supply must increase by 40%. Tedros Adhanom Ghebreyesus, the WHO director-general, says, “we can't stop COVID-19 without protecting health workers first.”   France has limited the use of FFP2 (KF94) respirators for health professionals that are treating the infected. The French government has recalled surgical masks to secure the necessary quantity of masks. Despite the government’s advice that the masks are ineffective as preventative measures for the general public without contact to the infected, masks and sanitizers have been stolen from the public healthcare system.

■ Priorities for Everyone

Dr. Tak Sang-woo (Seoul National University Institute of Health and Environment) has worked as an epidemiologist for the American Center for Disease Control and the Korean Ministry of National Defense. Epidemiology is a field that looks at the system beyond the individual influences. Dr. Tak states, “There has been a reversal of priorities in perspectives regarding masks. Given asymptomatic infections, it is understandable that masks are recommended in general. However, we must examine if the health professionals, the responders, are being protected first and foremost. It is more dangerous for those who need ten masks a day to use one. If the responders, health professionals are put in danger, it all affects the general public in the end. The principle of prioritization must not be shaken.”

Medical staff ready for the next shift at Keimyung University Daegu Dongsan Hospital on March 11. ⓒSisaIN Shin Seon-yeong

The Korean government has centralized the supply of masks at the Public Procurement Service so that the healthcare facilities do not have problems in securing masks. The Public Procurement Service signs contracts with all mask production firms, and distributes the masks through the Korean Hospital Association, the Korean Medical Association, the Korean Dental Association, and the Association of Korean Medicine. Hospital-level healthcare facilities may apply for surgical masks and respirators as needed on a weekly basis, depending on the number of workers and of hospital beds. Nonetheless, some frontline medical sites still tightly ration personal protective equipment such as masks. Nursing home care professionals, a high-risk group for infections, are a blind spot for masks as hospitals do not provide them with masks. Dr. Tak states that after healthcare professionals and disinfection providers, the next priority should be those who find it difficult to engage in social distancing due to livelihood needs.   On March 17, Dr. Zeynep Tufekci, an associate professor of information science at the University of North Carolina, wrote in her opinion piece “Why Telling People They Don’t Need Masks Backfired” in the New York Times that “Research shows that during disasters, people can show strikingly altruistic behavior, but interventions by authorities can backfire if they fuel mistrust or treat the public as an adversary rather than people who will step up if treated with respect.” In the band-aids on nurses’ faces and someone leaving ten to twenty masks they saved in front of the police office, we can find evidence of this altruism.   To wear, or to not wear a mask, is an important question. But to survive the age of COVID-19, another question must be prioritized. The question of “who should first wear the masks?” hides behind the frenzy for masks.   

translated by Jeongeun Park translation supervised by Franz Maier, Sumi Paik-Maier

 

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