Covid-19 and protective masks. Which ones to choose, for common and professional use? When, how, and why to use them, with the goal of protecting ourselves and our neighbors from Coronavirus transmission? ABC to follow.
Masks, three categories
Three types of protective masks are essentially available on the market, each with its own function.
1) Cloth masks. Made of cotton or synthetic materials, cloth masks are used in some work environments (e.g., food industry) as a basic hygienic practice.
2) Surgical masks. Clinical masks are not medical devices designed to prevent the spread of infection because they do not seal the face, and their effectiveness varies with their filtration capacity.
3) Respirators, with and without filter. Respirators are the only devices specifically designed to protect the individual from respiratory infections. They seal the face, around the nose and mouth.
Masks and respirators, the difference
Fabric masks, such as surgical masks are called ‘facemasks’ (facemask). They are not designed to protect the respiratory tract of the wearer and offer no guarantees in this regard. Their use has, moreover, been recommended-as a minimal barrier, ‘better than nothing‘-in some epidemic settings where surgical masks or respirators were not available. (1)
Respirators are classified as PPE ( Personal Protective Equipment, or PPE). They are governed by international standards and subject to appropriate certifications, the reliability of which it is always advisable (proper, in the professional sphere) to verify. They are ranked on the basis of their filtering effectiveness (FF), on a scale rising from P1 to P3. FFP2 and FFP3 models are the most indicatIve for virus protection. (2) Code N95 indicates the ability to block at least 95 percent of very small (0.3 microns) particles and is also available in a surgical-use version.
Masks, the general function
The general function of face masks is primarily to limit the risk of spreading infection when worn by infected people. Which, remember, can transmit some viruses even before the onset of symptoms or in their absence (in 44 percent of cases, according to a very recent observational study conducted by the Department of Science and Technology of Guandong Province, China). (3)
The spread of influenza virus from a sick patient wearing surgical masks or N95 can actually be reduced, according to an experimental study. (4) Another study conducted on volunteers with flu symptoms had shown that their use of a surgical mask could reduce viral particle emissions by a factor of three. (5) On the other hand, the widespread use of cloth and surgical masks proved effective in mitigating the SARS epidemic in Taiwan. (6) So in Hong Kong, where 76 percent of the population has worn them. (7)
Frequent and thorough hand washing, as noted above, is moreover essential precisely for the purpose of reducing the risks of infection through contact of contaminated hands with the eyes, nose and mouth. To the point that in the numerous studies conducted on communities undergoing various viral phenomena, it is difficult to attribute a preponderant preventive role to mask use.
Vulnerable people, the function of masks
The most vulnerable people -the elderly(over-65s), the immunocompromised, and people with other diseases (e.g., the cardiovascular and neurological conditions, diabetes, etc.)-must avoid external contacts or at least reduce them to the essential minimum. And that is why the ‘Cura Italia’ decree gives them priority in agile work (or teleworking). They still need to wash their hands often during this epidemic phase and live in environments with frequently sanitized surfaces and objects.
In any case, it is recommended that these individuals-as they are more susceptible to infection and the consequences of the coronavirus-wear a mask if they are forced to leave the house. As was recommended by health institutions in 2009, at the time of the so-called avian flu. (8) And in previous studies on how to mitigate the effects of epidemics on weak segments of the population. (9)
Égalité has launched a petition-which we urge everyone to sign, following this link-to urge supermarkets and ecommerce operators to guarantee free grocery delivery to the disabled, immunocompromised and over-65s. Precisely in order to spare them the strenuous and dangerous outings otherwise necessary to purchase essential goods.
Devices to be used in workplaces, a duty watered down in Protocol 14.3.20
Randomized clinical trials suggest the general protective role of face masks(facemasks) against infection in various community settings, within the limits of mask compliance and early use in case of infection. That must be constant during the coronavirus emergency, in the writer’s opinion, where businesses continue production activities.
The Protocol signed on 14.3.20 by the social partners, in Italy, merely provides for compliance with WHO recommendations on the use of masks. The bare minimum but certainly not enough, here and now, to prevent serious damage to workers’ health. As well as the contagion of third parties and entire communities. (10) With as many risks, for the legal representatives of the companies, of conviction for serious crimes.
Worker safety, mask or respirator?
Scientific evidence shows that respirators offer superior protection to masks(facemasks). They are therefore indispensable for health care workers and also for workers whom Protocol 14.3.20 woefully admits may work at interpersonal distances less than the minimum safe distance (1 meter). All the more so as they are exposed to contact with a plurality of people.
A surgical mask may be effective in blocking splashes and droplets of large particles, but it cannot filter out very small particles released into the air by coughs and sneezes from nearby people. Nor can it provide complete protection from germs and other contaminants, due to defect of complete adherence between the surface of the face mask and the face.
In fact, a scientific study of health care workers showed that N95 respirators significantly reduced the risk of bacterial colonization both compared with not using any protection (-62%) and compared with surgical masks (-46%). Which therefore proved ineffective for that purpose. The researchers went on to show how N95 masks can significantly reduce the risk-identified as common, among health workers-of simultaneous infection with bacteria and viruses. (11)
Italy, mask emergency. Ready ISS
The Ministry of Health, in circular 13.3.20, pointed out that surgical masks made of ‘nonwoven fabric’ (TNT), in order to be used as medical devices, must meet the following characteristics:
– Compliance with UNI EN ISO 14683, UNI EN ISO 10993 standards,
– production by enterprises with a (certified) quality system. (12)
DL 2.3.20 had, moreover, authorized the Civil Defense, until the end of the emergency period, to purchase personal protective equipment and other medical devices-including masks-even without the CE mark, after evaluation by the ISS (Istituto Superiore di Sanità. (13) Thus, the COVID-19 Medical Devices Working Group was tasked to assess the suitability of face masks for medical use, albeit without the CE mark. With a view to their use as an exception, limited to the emergency period. Interested operators can address their inquiries by writing to mascherinecovid-19@pec.iss.it.
Isolation and incubation period, latest studies
A very recent study analyzes the evolution of COVID-19 infection, comparing the Chinese example of strict quarantine (in Wuhan, where on 19.3.20 for the first time no new positive cases were reported) with the Italian experience of progressive (and not as strict) lockdown in northern Italy. To confirm how isolation is the only truly effective strategy. (14)
The incubation period of Covid-19-according to another very recent study based on the observation of 2015 cases (including 99 children) in 28 provinces in China-is moreover longer than the 14 days so far indicated by the WHO (or WHO, World Health Organization). In 233 cases out of 2015. Up to 33 days in some cases. Chinese researchers therefore recommend extending the minimum isolation period to 18, or even better to 21 days. (15)
Dario Dongo
Notes
(1) Institute of Medicine. Reusability of facemasks during an influenza pandemic: facing the flu. National Academy of Sciences, 2006. www.nap.edu/openbook.php?record_id=11637.
Association for Professionals in Infection Control and Epidemiology (APIC).
APIC position paper: extending the use and/or reusing respiratory protection in healthcare settings during disasters
. 2009.
(2) Institute of Medicine (IOM) National Academy of Sciences. (update 2010). Preventing transmission of pandemic influenza and other viral respiratory diseases: personal protective equipment for healthcare personnel. National Academies Press, 2010. ISBN-13: 978-0-309-16254-8 https://www.ncbi.nlm.nih.gov/books/NBK209584/
Siegel JD, Rhinehart E, Jackson M, Chiarello L. (2007). Guideline for isolation precautions: preventing transmission of infectious agents in health care settings. Am J Infect Control 2007;35(10 suppl 2):S65-164 https://www.ncbi.nlm.nih.gov/pubmed/18068815
(3) Xi He, Eric HY Lau, Peng Wu, Xilong Deng, Jian Wang, Xinxin Hao, Yiu Chung Lau, Jessica Y Wong, Yujuan Guan, Xinghua Tan, Xiaoneng Mo, Yanqing Chen, Baolin Liao, Weilie Chen, Fengyu Hu, Qing Zhang, Mingqiu Zhong, Yanrong Wu, Lingzhai Zhao, Fuchun Zhang, Benjamin J Cowling, Fang Li, Gabriel M Leung. (2020).
Temporal dynamics in viral shedding and transmissibility of COVID-19
. MedRxiv (peer-review study pending). doi: https://doi.org10.1101/2020.03.15.20036707
(4) Johnson DF, Druce JD, Birch C, Grayson ML. (2009). A quantitative assessment of the efficacy of surgical and N95 masks to filter influenza virus in patients with acute influenza infection. Clin Infect Dis 2009;49:275-7 https://www.ncbi.nlm.nih.gov/pubmed/19522650
(5) Milton DK, Fabian MP, Cowling BJ, Grantham ML, McDevitt JJ. (2013). Influenza virus aerosols in human exhaled breath: particle size, culturability, and effect of surgical masks. PLoS Pathogens 2013;9:e1003205. https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1003205
(6) Chen YC, Chen PJ, Chang SC, Kao CL, Wang SH, Wang LH, et al. (2004). Infection control and SARS transmission among healthcare workers, Taiwan. Emerg Infect Dis 2004;10(5):895-898. doi:10.3201/eid1005.030777 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3323237/
(7) Lo JY, Tsang TH, Leung YH, Yeung EY, Wu T, Lim WW. Respiratory infections during SARS outbreak, Hong Kong, 2003. Emerg Infect Dis 2005;11:1738-41 https://www.ncbi.nlm.nih.gov/pubmed/16318726
(8) Center for Disease Control and Prevention. (2009).
Interim recommendations for facemask and respirator use to reduce 2009 influenza A (H1N1) virus transmission
. www.cdc.gov/h1n1flu/masks.htm
(9) Bell D, Nicoll A, Fukuda K, Horby P, Monto A, Hayden F, et al. (2006) Non- pharmaceutical interventions for pandemic influenza, national and community measures. Emerg Infect Dis 2006;12:88-94 https://dx.doi.org/10.3201/eid1201.051371
(10) WHO (2020). Use of face masks (to reduce the risk of COVID-19 virus transmission). Recommendations, https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public/when-and-how-to-use-masks
WHO recommends the use of masks only under specific conditions (e.g., cough, fever, and difficulty breathing). However, neglecting the risks of transmission in pre-symptomatic or asymptomatic stages, already established in the Covid-19 pandemic (!)
(11) MacIntyre CR, Wang Q, Rahman B, Seale H, Ridda I, Gao Z, et al. Efficacy of face masks and respirators in preventing upper respiratory tract bacterial colonization and co-infection in hospital healthcare workers. Prevent Med 2014;62:1-7. https://doi.org/10.1016/j.ypmed.2014.01.015
(12)
TNT masks
– Epidemiological emergency information from COVID-19. Circular Min. Sal.13.3.20 http://www.trovanorme.salute.gov.it/norme/renderNormsanPdf?anno=2020&codLeg=73665&parte=1%20&serie=null
(13) DECREE-LAW March 2, 2020, No. 9. Urgent support measures for families, workers and businesses related to the epidemiological emergency from COVID-19. V. articolo 34, su https://www.iss.it/documents/20126/0/DECRETO-LEGGE+2+marzo+2020%2C+n.+9.pdf/997f707f-6c8f-530c-e82f-589824935cbb?t=1584545708698
(14) Marek Kochanczyk, Frederic Grabowski, Tomasz Lipniacki. (2020).
Impact of the contact and exclusion rates on the spread of COVID-19 pandemic.
MedRxiv ( peer-reviewed study pending). doi: https://doi.org/10.1101/2020.03.13.20035485
(15) Xue Jiang, Yawei Niu, Xiong Li, Lin Li, Wenxiang Cai, Yucan Chen, Bo Liao, Edwin Wang. (2020). Is a 14-day quarantine period optimal for effectively controlling coronavirus disease 2019 (COVID-19)? MedRxiv (peer-review study pending). doi: https://doi.org10.1101/2020.03.15.20036533
Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE - GIFT - Food Times) and Égalité.