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April 29, 2020

Moving Personal Protective Equipment Into the Community: Face Shields and Containment of COVID-19

Author Affiliations
  • 1Center for Access & Delivery Research and Evaluation, Iowa City VA Health Care System, Iowa City, Iowa
  • 2Carver College of Medicine, Department of Internal Medicine, The University of Iowa, Iowa City
JAMA. 2020;323(22):2252-2253. doi:10.1001/jama.2020.7477

On March 19, 2020, California became the first state to issue a stay-at-home order in response to the evolving coronavirus disease 2019 (COVID-19) pandemic. It was quickly recognized that widespread diagnostic testing with contact tracing, used successfully in countries such as South Korea and Singapore, would not be available in time to significantly contain the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).1,2 Over the following month, additional nonpharmaceutical mitigation strategies, including school closures, bans on large in-person gatherings, and partial closures of restaurants and retail stores, were applied to “flatten the epidemic curve” and limit the peak effects of a surge of patients on health care systems. Yet, even as the benefits of mitigation bundles have not fully been realized, there are widespread calls to reopen businesses, given the immense economic and social consequences of extreme physical distancing strategies.

Recently, public health, infectious disease, and policy experts have outlined recommendations for gradually reopening society using combinations of containment and mitigation strategies.3,4 Proposed containment strategies have followed the South Korean model and include rapidly expanding public health infrastructure for widespread testing and data-driven contact tracing, while ensuring that safe medical care is delivered by health care workers wearing adequate personal protective equipment (PPE), such as N95 respirators, medical masks, eye protection, gowns, and gloves. However, there is growing recognition that containment strategies that rely on testing will be inadequate because the necessary testing capacity may not be available for weeks to months, and in the US the ability to track, trace, and quarantine is unclear. In addition, countries where testing was not limited and containment was achieved, eg, Singapore, have seen substantial second waves of infection and mandated extreme distancing interventions that the US and other countries are trying to scale back.

The Infectious Diseases Society of America (IDSA) has included societal use of PPE, such as masks and face shields, in its recommendations for easing restrictions.4 Experience and evidence, even during this pandemic, suggest that health care workers rarely acquire infections during patient care when proper PPE is used and that most of their infections are acquired in the community where PPE is typically not worn.5 Thus, it becomes important to know if practice from occupational safety can be used in the community as a bridge to longer-lasting measures, such as vaccines. Could a simple and affordable face shield, if universally adopted, provide enough added protection when added to testing, contact tracing, and hand hygiene to reduce transmissibility below a critical threshold?

COVID-19 Transmission in the Community

The mode of transmission of respiratory viruses has long been a subject of debate. Evidence to date suggests that SARS-CoV-2 is spread like other respiratory viruses: by infectious droplets emitted in close proximity (ie, within 6 feet) to the eyes, nose, or mouth of a susceptible person, or by direct contact with those droplets (eg, touching a contaminated surface and then touching the eyes, nose, or mouth).6 Although droplet vs airborne transmission is likely to be a continuum, with smaller droplets able to be propelled further than 3 to 6 feet and remaining airborne longer after certain respiratory emissions,7 the implications of limited aerosol spread are most important in health care settings after aerosol-generating procedures, such as open suctioning of airways and endotracheal intubation or extubation.

Contact investigations for SARS-CoV-2 have confirmed community transmission rates that are consistent with droplet and contact spread (household attack rates of 10%, health care and community attack rates of <1%, and R0 [the effective reproduction number, or average number of new infections caused by an infected individual during their infection] of 2-3),5 and much different than for airborne viral pathogens, such as varicella zoster virus or measles (household attack rates of 85%-90% and R0 of 10-18).

This implies that simple and easy-to-use barriers to respiratory droplets, along with hand hygiene and avoidance of touching the face, could help prevent community transmission when physical distancing and stay-at-home measures are relaxed or no longer possible. The 2 major options for such barriers are face masks and face shields.

Face Masks and Face Shields

The supply chain for medical masks is concentrated in China and the origin of the outbreak there resulted in factory closures and critical shortages. To preserve medical masks for health care facilities, the Centers for Disease Control and Prevention has recommended that all persons wear a cloth mask in public for source control. Cloth masks have been shown to be less effective than medical masks for prevention of communicable respiratory illnesses,8 although in vitro testing suggests that cloth masks provide some filtration of virus-sized aerosol particles.9 Face shields may provide a better option.

Face shields come in various forms, but all provide a clear plastic barrier that covers the face. For optimal protection, the shield should extend below the chin anteriorly, to the ears laterally, and there should be no exposed gap between the forehead and the shield’s headpiece. Face shields require no special materials for fabrication and production lines can be repurposed fairly rapidly. Numerous companies, including Apple, Nike, GM, and John Deere, have all started producing face shields. These shields can be made from materials found in craft or office supply stores. Thus, availability of face shields is currently greater than that of medical masks.

Face shields offer a number of advantages. While medical masks have limited durability and little potential for reprocessing, face shields can be reused indefinitely and are easily cleaned with soap and water, or common household disinfectants. They are comfortable to wear, protect the portals of viral entry, and reduce the potential for autoinoculation by preventing the wearer from touching their face. People wearing medical masks often have to remove them to communicate with others around them; this is not necessary with face shields. The use of a face shield is also a reminder to maintain social distancing, but allows visibility of facial expressions and lip movements for speech perception.

Most important, face shields appear to significantly reduce the amount of inhalation exposure to influenza virus, another droplet-spread respiratory virus. In a simulation study, face shields were shown to reduce immediate viral exposure by 96% when worn by a simulated health care worker within 18 inches of a cough.10 Even after 30 minutes, the protective effect exceeded 80% and face shields blocked 68% of small particle aerosols,10 which are not thought to be a dominant mode of transmission of SARS-CoV-2. When the study was repeated at the currently recommended physical distancing distance of 6 feet, face shields reduced inhaled virus by 92%,10 similar to distancing alone, which reinforces the importance of physical distancing in preventing viral respiratory infections. Of note, no studies have evaluated the effects or potential benefits of face shields on source control, ie, containing a sneeze or cough, when worn by asymptomatic or symptomatic infected persons. However, with efficacy ranges of 68% to 96% for a single face shield, it is likely that adding source control would only improve efficacy, and studies should be completed quickly to evaluate this.

Major policy recommendations should be evaluated using clinical studies. However, it is unlikely that a randomized trial of face shields could be completed in time to verify efficacy. No clinical trial has been conducted to assess the efficacy of widespread testing and contact tracing, but that approach is based on years of experience. Taken as a bundle, the effectiveness of adding face shields as a community intervention to the currently proposed containment strategies should be evaluated using existing mathematical models. The implicit goal of face shields alone or in combination with other interventions should be to interrupt transmission by reducing the R0 to less than 1. Notably, effective control of even the most infectious pathogens, such as measles, does not require a vaccine with 100% efficacy. No burden of 100% efficacy should be placed on face shields or any containment policy because this level of control is both impossible to achieve and unnecessary to drive SARS-CoV-2 infection levels into a manageable range.


The COVID-19 pandemic arrived swiftly and found many countries unprepared. Even highly prepared countries are now facing second-wave outbreaks that have forced implementation of extreme social distancing measures. To minimize the medical and economic consequences, it is important to rapidly assess and adopt a containment intervention bundle that drives transmissibility to manageable levels. Face shields, which can be quickly and affordably produced and distributed, should be included as part of strategies to safely and significantly reduce transmission in the community setting. Now is the time for adoption of this practical intervention.

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Article Information

Corresponding Author: Eli N. Perencevich, MD, MS, Iowa City VA Health Care System, 601 Hwy 6 W, Iowa City, IA 52246 (eli-perencevich@uiowa.edu).

Published Online: April 29, 2020. doi:10.1001/jama.2020.7477

Conflict of Interest Disclosures: Dr Diekema reported receiving research funding from bioMerieux. No other disclosures were reported.

Disclaimer: The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of the Department of Veterans Affairs or the US government.

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Infectious Diseases Society of America. Policy and public health recommendations for easing COVID-19 distancing restrictions. Published April 16, 2020. Accessed April 19, 2020. https://www.idsociety.org/contentassets/9ba35522e0964d51a47ae3b22e59fb47/idsa-recommendations-for-reducing-covid-19-distancing_16apr2020_final-.pdf
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8 Comments for this article
Safety Guidelines for Face Shield Preparations and use
Dr Mubarak M Khan, MBBS, DLO,DNB (ENT) | Sushrut ENT Hospital & Dr Khan’s Research Centre, Pune, India
In the wake of scarcity of face shields during the COVID-19 pandemic, consideration of innovating newer methods of manufacturing must be considered to overcome the present day scarcity without jeopardising the safety of front line Heath care workers.

All safety precautions and guidelines for use and disposal and sterilisation must be considered to get maximum benefits out of such simple innovations. Hence we thought of putting down simple guidelines for new emerged face shield use:

1. Snug fitting.
* The face shield must be tightly fitting around head without any gaps between forehead and shield
* All
3D printed or readymade plastic bands don't achieve this
* A simple solution is to tie the shield firmly with an elastic band (which may give headache due to pressure if used for long time) or simple ribbon gauge

2. Tight fitting
* All 3D printed or readymade plastic used for holding is best for single use. With repeated use, the face shield may fall while working
* Using a sponge in between the forehead and face shield gives good comfort as well as a snug fit, but such face shields should be considered disposable because sterilisation of all material is incomplete

3. Disposable/Reusable
* If you are using the face shield as disposable then it’s best use it once and with utmost care remove it after use and dispose it properly. See sterilisation
* Reusable Face Shields: if you plan to reuse the face shield, utmost care should be taken while removing the shield after use and then sterilise it before reuse. See sterilisation
* Reusable face shields must be very simple prepared based on above points and must be free from any sponges or sticking material or stapler pins to achieve good sterilisation
* Minimum 5 reusable face shields must be kept in reserve to use it alternately with sterilisation

4. Quality of Material for face shield
* No plastic or OHP sheet < 50 micron should be used for face shield due to possibility of crimping and movement due to air flow
* Best thickness is OHP of 150 to 200 micron (for repeated sterilisation and handling and avoiding crimping )

5. Methods of Handling
* Never touch the front side of OHP/ face shield
* Never hold face shields by touching plastic of OHP sheets
* after complete use, with hand in gloves 🧤removing face shields from behind by untying the ribbon knot or releasing the visor or lifting the readymade plastic head band over ear
* If you are disposing the face shield , dispose it along with your gloves
* If you are reusing the face shield, follow the methods of sterilisation

6. Methods of sterilisation
* The removed face shields must be kept in 1% Sodium Hypochlorite solution (see how to prepare it) for 10 minutes
* Dry it in sunlight
* after complete drying, Clean it with Sanitisers (very crude method) (see how to make sanitiser by yourself) (everything must be done with hand in gloves)
* Or keep face shields in 2% Glutaraldehyde for 10 min, wash it with normal saline, again dry it
* Best way of sterilisation is ETO

7. Considering all above points, it’s prudent to avoid all supplementary materials like sponge, stapler pins, sticking materials, adhesives and any other fancy materials for aesthetic appeal (if you are reusing the face shields)

8. The simplest way of preparing the face shields is
a. Take an A4 size OHP sheet of 150 to 200 micron thickness
b. With an office punching machine, make 8 holes across length of the OHP sheet, leaving a 2 cm margin
c. Thread cotton ribbon gauze of 60 cm alternately through created holes for tying around head
d. Your simple face shield is ready
Cleaning Face Shields
Jane Wilcock, MBChB | GP Practice: Silverdale Medical Practice, Salford, UK
Great article, I absolutely agree with face shields (visors) as the action for public use post-lockdown to prevent a second peak with physical distancing and continued hygiene, especially hand washing. Commonly made in the UK by firms, crafters and schools ,the plastic should be recyclable so would reduce waste.

Cleaning: I read the comments on safety from Dr Khan recommending sodium hypochlorite to clean but why not alcohol or soap and water? That's whatswe've all have at home. My visor recommends alcohol, but why not soap and water?
Cleaning Face Shields
Kamal Kishore, MD, MBBS | Illinois Retina and Eye Associates, Peoria, IL
I like Dr. Khan's idea of homemade face shields. Very ingenious!
I have a few comments regarding proposed cleaning methods
1. Glutaraldehyde (Cidex) has environmental concerns and has been banned at most places in the US.
2. According to the EPA, ETO is carcinogenic and this method of sterilization is not readily available in the US
3. Bleach (2% dilution of 5.25% commercially available solution, according to the CDC) will work but irritates the eyes and has to be used with good air flow and gloves
4. That leaves either 0.5% hydrogen peroxide wipes, or alcohol wipes. They both
work. Take your pick
5. Either one of them will kill this virus after one minute of contact.
6. I see nothing wrong with soap and water. This is an enveloped virus and very easy to kill.
7. Since the virus doesn't survive beyond three days on any surface (NEJM article), there is nothing wrong with having four face shields. Leave the shield in a breathable bag for three days and reuse it.
8. Leaving your shield in direct sunlight will kill this virus within minutes. To be extra safe, you can leave your shield in full sun for 30 minutes, preferably outside because wind also inactivates this virus.

Hope it helps.
Thanks for your comments.
Face Masks and Shield-Wearing in the Community Should be Considered when Exiting Societal Lockdown
An Pan, PhD | Huazhong University of Science and Technology
The COVID-19 pandemic has swiftly swept the world, causing more than 240,000 deaths among over 3.5 million confirmed cases as of May 6, 2020. After weeks’ of social distancing policy and stay-at-home orders, many countries and many states in the US have started to relax restrictions and reopen businesses under the enormous economic and social stress. We fully agree with Dr. Perencevich that the combinations of containment and mitigation strategies are needed when reopening society (1). 

We have previously shown that the combinations of public health interventions have quickly suppressed the outbreak in Wuhan (2). The experience in the
past one month in Wuhan since its reopening on April 8 may also provide clues for the exit strategies.

As Dr. Perencevich mentioned, adequate testing and active contact tracing are important. In the past month, to prepare for the business reopening, more than 1.1 million nucleic acid tests were perform in Wuhan and >600 asymptomatic cases were identified and >2500 close contacts were traced. Employees in the essential sectors, such as hospitals and clinics, education facilities, and service sectors were required to get nucleic acid tests or antibody results. The tests are now included in the medical insurance scheme and the out-of-pocket payment was about 10%-30%. However, it should be noted that testing per se is insufficient to contain the outbreak, and the ability to track, trace and quarantine after testing is also crucial, as shown in China and South Korea.

Meanwhile, community actions are needed. In February in Wuhan, the government initiated two waves of community symptom screening to identify potential cases, isolate the source of infection and block the transmission route. Although it was argued whether the screening was necessary to drive the reproduction number below 1.0, the strategy helped quickly crush the epidemic curve and dramatically reduced the number of incident cases. Since February, people were required via online platforms to report fever and respiratory symptoms. Temperature screening has been widely enforced in public places. Those with symptoms should get immediate medical attention and be tested as soon as possible.

In addition, transmission from asymptomatic infected cases has been documented (3) and over 40% of secondary cases were infected during the index cases’ presymptomatic stage (4). Therefore, facial covering is necessary to block the transmission and prevent these apparently healthy infectious sources. Accumulating evidence now demonstrates that mask-wearing is efficient to protect people from infection (5). As governments plan how to exit societal lockdowns, face masking in crowded public areas or unknown-risk areas, particularly in closed rooms, could be a key component of public health interventions for containing the pandemic and preventing a major second wave (5). Face masks have been widely encouraged and compulsorily required in public places in Asian countries. There are increasing voices for the shift of culture stigma for healthy people wearing face masks in the community and that mask/shield-wearing could be considered in the Western countries. Broad support and clear guidance are needed from the governments and various health organizations. The viewpoint paper by Dr Perencevich and his colleagues is an important piece in this context.

With Prof Tangchun Wu from HUST.

1. JAMA. doi:10.1001/jama.2020.7477.
2. JAMA. doi: 10.1001/jama.2020.6130.
3. JAMA 2020;323(14):1406-7.
4. Nat Med. DOI: 10.1038/s41591-020-0869-5.
5. https://arxiv.org/pdf/2004.13553.pdf
Transparent Face Masks Cannot Prevent Microbial Inhalation
Tang Lee, Building Scientist | University of Calgary, Canada.
Transparent face masks have many advantages as discussed in this article and remarks. However, they cannot protect from airborne infectious diseases. Breathing in will draw airborne microorganism into the space behind the face mask which then can enter the lungs. The only way to prevent drawing in airborne microbes into the transparent face mask is with a positive air pressure. This will require a fan that blows air between the transparent face mask and the face. However, the air must have germicidal properties and also remove any volatile organic compounds, and airborne particulates.
Evidence For the Efficacy of Medical Masks and Respirators.
Gary Ordog, MD, DABMT, DABEM | County of Los Angeles, Department of Health Services, Physician Specialist (retired)
Thank you for your excellent and timely article. I wish to respond to a controversial comment by Dr. Thomas Pliura. He implied that there are no research studies published on the preventive efficacy of facial masks and shielding (I will include respirators to be more complete): "I ask for a single citation to a validated study to support the premise that face masks would do anything at all to contain the spread of COVID-19." Five simple Med-Line searches with those words, virus, and efficacy, yield around well over 100 peer-reviewed articles, including several from the COVID era. Additional searches on studies of safety yielded over a thousand research articles, including recently in this very journal, JAMA. Would there even be a century of wearing surgical masks if they weren't useful in the prevention of transmission of infectious agents? I daresay that most or all of our healthcare workers would currently be SARS-CoV-2 positive if not for PPE. Please review and reconsider your comments. Thank you and stay safe.
Misinformation on Face Shield Efficacy
John Murphy, MHSc PhD ROH CIH MACE | University of Toronto, Dalla Lana School of Public Health
Citing Lindsey et al (reference 10) the authors state “face shields were shown to reduce immediate viral exposure by 96%” and “face shields blocked 68% of small particle aerosols, which are not thought to be a dominant mode of transmission of SARS-CoV-2.” The 96% reduction observed by Lindsey et al was due entirely to attenuation of large droplets (i.e. 50 to 100 µm) which behave ballistically and constituted most of the 62 µl volume of the experimental cough. Attenuation of large droplets by a face shield could only lessen community transmission if persons with COVID-19 expelled larger droplets exclusively. However, coughs and exhalation generate droplets mainly in range of <0.5 to 20 µm, which do not behave ballistically, meaning the large droplet protective value of face shields affords no protection from SARS-CoV-2 virions in coughs and breath. There is also growing evidence that inhalation of respirable droplets generated simply by exhalation that can circumvent a face shield may be a dominant mode of community transmission.

The authors also claim that Lindsey et al found “face shields blocked 68% of small particle aerosol”. That is not correct. Lindsey et al's small aerosol trial found virus deposition (not particle aerosol concentrations) were reduced by 68%, which was also due to the ballistic attenuation of the larger droplet fraction.

Perencevich et al also fail to explain that in the Lindsey et al study the aerosol particle concentrations initially produced by the cough simulator were so high they exceeded the upper detection limit of the particle counter, whether or not a face shield was worn. This finding precludes drawing any conclusion about face shield attenuation efficacy.

While the Lindsey et al paper is the foundation for the Perencevich Viewpoint, the former authors make no suggestion that face shields have any role in prevention of community transmission, stating “they cannot be used as a substitute for respiratory protection when it is needed.”

With the imprimatur of JAMA, many media outlets have quoted the Perencevich et al paper as evidence that face shields in community settings will protect against COVID-19 transmission. If some manner of respiratory protection is warranted in community settings, the suggestion that face shields are suitable alternatives to masks is misinformation that could have adverse consequences.

There is an understandable public and government appetite for authoritative information on effective infection prevention and control measures for COVID-19. This implies a need for JAMA authors, editors and peer reviewers to exercise a much higher standard of care with respect to the evaluation of science-based opinion than appears to have been the case with this paper.
Use of the Assessment, Mitigation, Performance Model for community level management of COVID-19
Rahul Narang, MBBS, MD, PhD | Professor, Microbiology, Mahatma Gandhi Institute of Medical Sciences, Sevagram, Wardha, Maharashtra, India
The Assessment, Mitigation, Performance (AMP) Model has been used in biorisk management for at least a decade (1). In this model, the risk associated with an agent is assessed, mitigation measures are applied to reduce the risk, and performance of such measures is noted over period of time. In fact, the field of biorisk management originated in 2000s after a number of biological laboratory incidents involving dangerous agents. As the world is facing an enhanced risk of COVID-19 and the countries have to unlock themselves, we feel the same model may be applied to day-to-day activities of the population in various situations.
The disease is caused by SARS-CoV-2, a positive sense single strand RNA virus that is liberated mainly from the respiratory tract when the person harboring this virus breathes, talks, sings, sneezes and coughs. Even if it may not be as airborne as Mycobacterium tuberculosis or measles virus, still in small congested spaces where ventilation is poor and the number of humans is more, the risk of spread of COVID-19 is enhanced.
To mitigate this risk, the general public may be trained by way of pre-tested check lists in their local language to assess the risk with various kinds of activities that the individual is likely to undertake on a day. For example, check lists may be developed for those travelling by public transport, visiting offices, shops, restaurants, clinics, hospitals, conferences and those attending school or college. Based on the assessment, the checklist may inform the risk and risk-prone areas during desired activity and final score of the checklist may guide the individual to take certain precautions, e.g. carrying masks and their number as some activities may require change of mask, face shields, sanitizer, hand washing and social distancing. Though all these measures have been promoted from the start of pandemic, with progression people are likely to become complacent.

Similarly, the indoor spaces at their entrance may post diagrammatic display of the requirements to enter, e.g. wearing masks or other PPE and may prohibit those who fail to comply.

Based on the above two functions of assessment and mitigation, longitudinal studies may be conducted to check the performance of such measures and if the results are encouraging, the policy makers will be able to design better control measures for COVID-19.


World Health Organization. 2012. Biorisk Management Advanced Trainer Programme. http://www.who.int/ihr/training/biorisk_management/en/accessed on 06.07.2020.