The pandemic of SARS-CoV-2 is a highly infectious Coronavirus that is spread primarily through droplet and airborne transmission and causes COVID-19, a dangerous and life-threatening illness, primarily of the respiratory tract. Adequately preparing a healthcare facility to respond to this outbreak is both challenging and daunting. The original SARS-CoV (SARS) outbreak in 2002 to 2003 disproportionately affected healthcare workers, which has been at least in part attributed to inadequate infection control standards.
This document is intended to serve as a guide and summary of existing best practices, standards, and regulations related to infection control and their application to SARS-CoV-2. The need for such guidance is brought into sharper focus by the global shortage of personal protective equipment (PPE) that has developed as this virus has spread around the world. Therefore, for each topic, we provide a summary of conventional worker protection strategies, acceptable alternate solutions, or adjuncts, and finally minimal standards that are appropriate only for crisis operations.
GUIDING PRINCIPLES OF THIS DOCUMENT
Standard precautions are a set of minimum best practices that are recommended by the Center for Disease Control (CDC) for use when workers may come into contact with bloodborne pathogens or any other potentially infectious material. These precautions were developed as a result of the uncertainty of the HIV/AIDS epidemic of the 1980s and include: hand hygiene, use of PPE (gloves, eye protection, etc), respiratory hygiene/cough etiquette, sharps safety, safe injection practices, sterile instruments and devices, and clean and disinfected environmental surfaces. These practices should form the cornerstone of any safe healthcare workplace.1
HIERARCHY OF CONTROLS
In addition to the standard precautions list above, additional precautions should be implemented with reference to the Hierarchy of Controls, a schema that organizes interventions in the workplace by different tiers of effectiveness in preventing workplace injury and exposure. These tiers include Elimination, Substitution, Engineering Controls, Administrative control, and PPE.2 Elimination is the identification and removal of unnecessary hazards; while substitutions replace a hazardous situation with a less dangerous one. Engineering control is the use of external barriers of systems to reduce exposure to healthcare workers (HCW) such as the use of physical barriers (eg, placing a glass or plastic windows in reception areas), enclosure, and isolation (eg, use of airborne isolation rooms for aerosol-generating procedures).2 Administrative controls are policies and practices designed to reduce HCW exposure to hazards. Although it is the most visible, PPE is the least effective type of protection in the hierarchy because it requires active, successful use on the part of the HCW and is therefore also the most susceptible to human error. Despite this, it is the final “fail-safe” in a worker protection strategy.
In this article, we present common-sense, readily applicable guidance on various topics in traditional domains of disaster management and planning, utilizing the “Stuff, Space, Staff, and Systems” paradigm while shaping this guidance into the hierarchy of controls schema that has already been introduced.3,4 In doing so, we will present Space and Staff problems and solutions first, as these elements track onto the first four most effective tiers of the Hierarchy, then progress to Stuff problems which generally center around PPE, with a running discussion of optimal Systems changes integrated throughout.
Some sources, including from the CDC state that elimination of an infectious disease hazard is not typically possible. However, we argue here that there are some select cases where “true” elimination is possible. We suggest that the typical definition of “physical removal of a hazard” is overly narrow, and elimination is more appropriately understood as “complete removal of a dangerous interaction between a hazard and a worker.” This may occur by removal of the worker from proximity to the hazard or removal of the hazard from the workplace. When understood this way, we suggest that telemedicine visits are an example of true elimination rather than administrative controls because although it is “changing the way people work” it also completely removes the dangerous interaction between the healthcare worker and the hazard (the COVID-19 patient). Similarly, restricting unnecessary access to the healthcare facilities is an example of elimination because it can prevent an infected, but asymptomatic visitor from interacting with healthcare workers, rendering that potential hazard (ie, infection) completely eliminated. Although superficially these are changes to the way people work, because they are completely removing the dangerous interaction, they are in fact at the apex of the hierarchy of controls rather than among the least effective strategies.
Similarly, examples of Substitution are limited since infectious diseases pose inherent hazards that cannot be replaced with less dangerous ones (ie, a less dangerous disease). However, in some cases, it may be better to understand the hazard not as the infectious disease itself, but rather as the risk-generating interactions that the HCW undertakes with it. One such example is Bilevel positive pressure ventilation (BiPap) which is thought to be an aerosol-generating procedure that creates an ongoing high-risk environment for nearby HCWs. If a hospital recommends endotracheal intubation be used instead of BiPap since this is thought to only be a transient risk during the initiation of the procedure, but not an ongoing risk of aerosolization for the remainder of the patient's ventilation, this could be seen as an instance of Substitution or as an administrative control depending on the context. If, hypothetically, the hospital implements a strict, universal ban on BiPap to prevent any possibility of its use on a COVID-19 patient this is Substitution; whereas if the new protocols are written to help HCWs when intubation is preferable to BiPap, then this is an Administrative Control. Our goal is not to definitively categorize each possible safety intervention, but rather to use the Hierarchy of Controls to characterize the risks that HCWs encounter and use that understanding to trend towards a safer workplace.
The first step in each healthcare facility's transition from routine operations to pandemic response should be to restrict its operations only to essential functions. Non-essential or elective procedures should be canceled, and routine office visits should be deferred. Access to the facility should be restricted to only those performing essential functions. This will be a frustrating and unpopular policy for patients and their families.5 However, reducing overall traffic through the healthcare facility reduces opportunities for healthcare workers to become infected and for facilities to become contaminated. It also enables healthcare workers to transition from their routine operations to dedicated pandemic response activities. Visitor access to the healthcare facility should be curtailed, with the possible exception of carefully selected circumstances such as pediatrics, labor and delivery, or end of life situations. Visitors and workers entering the facility should be evaluated for possible infectious symptoms prior to entry (eg, screening questionnaires and temperature screenings), and if positive, denied entry and referred for appropriate self-isolation. Thoughtful communication with patients and their families about the importance of such policies will be essential to their successful implementation.6
To the greatest extent possible, telehealth technology should be used to isolate patients, providers, and facilities from possible exposures. Routine ambulatory office visits should be transitioned to tele-visits, and for inpatient settings, transitioning specialist consultations to remote visits should be done if direct contact with the patient and care team is not absolutely necessary. Telemedicine monitoring within healthcare facilities should be used whenever possible to prevent unnecessary patient-HCW contact. Similarly, remote electronic communication with patients should be implemented whenever possible. As a secondary strategy, these policies may also be applied to patients hospitalized for non-COVID reasons, as their risk of new infection may actually be increased while inpatient due to HCWs high cumulative risk of exposure to SARS-CoV-2 and the possibility of asymptomatic carriers among the staff. Decreasing the number of non-essential patient interactions will also have the added benefit of decreasing PPE usage during the pandemic.
One of the lowest costs and most easily implemented interventions is to immediately require all patients and staff to wear surgical masks while on premises. This of course provides a reasonable baseline level of protection against respiratory droplets but can also serve as a mechanism for source control by preventing spread from persons infected with SARS-CoV-2. A significant portion of people infected may have minimal symptoms or be completely asymptomatic while unknowingly spreading the virus. Requiring mask use can substantially decrease asymptomatic spread of a droplet-transmission disease. Indeed, when community prevalence of the disease reaches sufficiently high levels, healthcare facilities should assume that a significant fraction of patients presenting for reasons other than COVID-19 symptoms or testing will also be carriers of the virus.
Consider creating discrete, well demarcated areas within each facility to quantify the amount of hazard present and to delineate when and where it is appropriate for staff to work. Such areas should be clearly identifiable as hot/warm/cold or red/yellow/green, and the transitions between areas should also be prominently and unambiguously identified. Details of such a system will necessarily vary between facilities but some examples include colored tape borders on walls and floors or high visibility signage on doors. Such markers should be made intelligible in languages specific to local staff and patient populations. Corresponding badging for staff may also be appropriate in some locations to quickly and easily identify persons entering into inappropriate areas.
Barrier shielding can be applied to a variety of situations within a healthcare facility and are especially appropriate for when droplets or aerosols are most likely to be encountered. A variety of such devices have been proposed including plastic barriers (with or without integrated gloves) between HCWs administering expedited testing and the patient, as well as so-called “aerosol boxes” which are reusable plastic shields to cover the patient's face and shoulder during intubation.7,8
Negative Pressure Rooms and Patient Cohorting
Negative pressure rooms use directional airflow and high efficiency particulate air (HEPA) filters to remove hazardous or infectious particles from the air and to decrease the risk of secondary contamination of other areas. Negative pressure rooms should be used for all known or suspected COVID-19 patients when feasible. These facilities should strictly adhere to the recommended maintenance and testing schedules. If pre-existing dedicated negative pressure facilities are not sufficient for patient volumes, temporary facilities can be created with commercially available modular negative pressure systems that convert existing spaces into negative pressure isolation systems. Custom or ad hoc systems may also be appropriate depending on local expertise.9 These offer the potential to create additional surge capacity for healthcare facilities. As patient volumes increase during the course of an outbreak, it is likely to outpace available isolation facilities. When it is no longer feasible to place all COVID patients in such rooms, they should instead be reserved for use during aerosol-generating procedures and patients should be moved in as necessary.
Similar opportunities to eliminate hazards exist by combining or shifting roles between providers. HCWs entering a room to perform an examination, collect samples, or administer therapeutics will necessarily take on a degree of risk, but this hazard is inherent to providing essential components of medical care. If these hazards are unavoidable, additional tasks that would traditionally be performed by other staff may be performed by those who are already being exposed to the hazard (hopefully already utilizing appropriate procedures and PPE to mitigate that risk). For example, a physician performing an initial assessment of a patient can then assist with obtaining a portable chest radiograph by placing the film behind the patient and positioning the x-ray machine within the room while the radiology technician remains outside the room with the trigger. This allows for conservation of PPE, since the radiology technician is no longer required to enter the room, dramatically decreasing their risk of exposure during this encounter. Appropriate protocols and training will need to be implemented in conjunction with these changes in roles, such as having the physician don a lead apron prior to PPE, and decontamination of the x-ray machine to prevent cross contamination of the technician and equipment.
As noted above, less specialized tasks should be combined with the routine duties of HCWs who are already performing unavoidable tasks that require hazard exposure. For specialized, high risk procedures, however, the reverse approach may be more appropriate. These can potentially be consolidated into specially trained and equipped teams of workers who are better prepared to deal with them. Having specialized teams of Anesthesia or Emergency HCWs immediately prepared for high acuity situations such as airway interventions or cardiopulmonary resuscitation (CPR) allows them time away from other duties to be more rigorously trained in such procedures and high level PPE usage, such as 100 level respirators or powered air-purifying respirators (PAPRs) that may be less suitable for general usage but quite appropriate for specialist use. Having such teams readily available can also head off the impulse of most HCWs to “rush in and help” during high acuity situations, since these are the times that are most prone to safety violations while also having high potential for droplet and aerosol exposure.10
Positive Pressure Ventilation
Some sources early in the pandemic response argued that BiPap posed an extremely high risk to providers relative to endotracheal intubation due to the increased potential for aerosolization of viral particles. Therefore, they advocated for progressing directly from maximal non-invasive oxygen supplementation (eg, non-rebreather or hi-flow nasal cannula), to elective intubation without attempting BiPap or CPAP therapy as might normally be done in other non-COVID-19 cases of respiratory distress. However, this proposal substitutes a non-invasive procedure (BiPap/CPAP) for an invasive one (endotracheal intubation) and will therefore include all the associated risks and complications of the intubation procedure. Furthermore, even if the patient tolerated the initial procedure without complication, some patients may experience delayed complications due to intubation. For example, weaning someone with advanced chronic obstructive pulmonary disease (COPD) and concomitant COVID-19 off of mechanical ventilation is likely to be more difficult and increases the risk of permanent ventilator dependence than if the same patient were managed on BIPAP alone. Whether the assumptions of this strategy hold (ie, BIPAP causes significantly more aerosolization than intubation and that mechanical ventilation is non-inferior to BIPAP) and whether such a strategy stands up to ethical scrutiny, is a topic that requires further investigation beyond the scope of this paper.
External Testing and Triage
The use of adjunct locations and facilities can be useful ways to concentrate and mitigate hazards outside of the hospital setting. Establishing drive-through or external testing sites can prevent suspected infected patients from entering clinics and hospitals, the efficacy of which was demonstrated in South Korea. This serves several useful functions, including removing the hazard from the main location, and allowing it to be more easily mitigated. Creating a select cohort of workers who will work in higher risk exposure areas such as dedicated testing areas is not without its risks but may also be appropriate if safety preparations are made. Such workers should be equipped with appropriate PPE, trained on its usage, and followed longitudinally to ensure that effective use is consistent over time. Some testing sites have tried to further decrease the risk to HCWs by having patients self-administer nasopharyngeal swabs or collect saliva samples from themselves and interim CDC guidelines allow for supervised self-collection of mid-turbinate swab or home collection of anterior nares swabs.11 While these are potentially valuable techniques, more research is needed to fully validate them and testing sites should be wary of the potential for increased false negative rates from self-administered tests since obtaining a mid-turbinate nasopharyngeal swab is a painful procedure. In appropriate circumstances, establishing triage facilities outside of the hospital can be an effective tool for hazard mitigation. Creating protocols for direct admission to the hospital or diversion to a designated treatment area can avoid congestion and contamination of the Emergency Department (ED). If a patient is already known to have tested positive for SARS-CoV-2 or has a suggestive history and physical examination (ie, a high pretest probability, which notably increases with community prevalence), and requires inpatient care for supplemental oxygen therapy, then they may not need ED evaluation. Such patients could be admitted directly to appropriate wards that are designated COVID-19 treatment units.
Donning and Doffing
In addition to the OSHA required yearly training for respiratory PPE, we strongly recommend that “just-in-time training” be offered for all relevant PPE as soon as the emergence of a new hazard has been identified in the local area. HCWs should be fully versed in the use of all relevant PPE during regular operations, but skills fade without use and people will naturally deviate from best practices. Accepting that these skill deficits and protocol deviations exist and addressing them through periodic and just-in-time training is crucial to employee safety. The frequency of scheduled retraining should be guided by active monitoring of compliance with best-practices.12
In addition to retraining, effective PPE use can be further increased by implementation of donning and doffing “buddy” systems to assist with the mechanics of the procedure as well as to supervise and correct errors in real time. Independent or efficiency minded HCWs may be resistant to such measures and perceive real-time supervision as demeaning or as wasting other workers’ time. These concerns should be specifically addressed by leadership, emphasizing that correct PPE usage is essential to protecting HCW health and safety and is seen as a priority over efficiency. Ideally, additional staff should be available to fill the role of PPE buddy to prevent disruption of overall workflow. These responsibilities can be easily filled by patient care techs or medical assistants.
Whenever possible, donning and doffing should occur in designated areas immediately adjacent to the patient care area. Ideally such areas would be an anteroom outside an isolation room, which provides an unambiguous transition from “clean” to “dirty” areas, limits inadvertent cross-contamination, and allows easy containment of contaminated laundry and waste streams. However, these will only rarely be able to be implemented de novo if not previously constructed. More likely, insufficient dedicated isolation rooms will be available, and therefore donning and doffing should occur immediately outside the patient's room and these areas can be identified by placing colored tape on the floor to discourage “wandering” of HCWs while in contaminated PPE.
While working in the high stress context of a pandemic response, HCWs can be tempted to relax their discipline during breaks and after shifts. This can lead to staff rushing through doffing and risking contamination of their clothes and bodies. Similarly, they may be tempted to congregate in break rooms or other common areas to eat or during shift change. This is more troubling since it occurs at times when they are less likely to be wearing masks or other types of PPE. Healthcare leaders should consider implementing occupancy limits for break rooms and staggering breaks among HCWs while also performing cleaning and disinfection of these common areas with increased frequency.
In certain situations, it may be appropriate to provide on-site or nearby dedicated housing for HCWs who are working with COVID-19 patients. Although such distancing from worker's families has the potential to be psychologically stressful, in context it may be a reassuring option if the affected HCWs normally live with persons vulnerable to COVID-19. This is an especially important option for workers in high risk areas and those who are asked to self-isolate.
Personal Protective Equipment
With respect to contact precautions, some of our recommendations are generalized from experiences in previous infectious disease outbreaks such as Ebola. Whether the same degree of contact precautions is necessary for COVID-19 is not clear. SARS-CoV-2 is far less lethal than Ebola and their mechanisms of spread do differ significantly in that Ebola has multi-modal spread from infected body fluids to mucus membranes whereas SARS-CoV-2 is thought to be primarily via respiratory droplets and aerosols, although it is believed to also have spread through mucous membranes. More importantly however, is that during the 2014 to 2015 Ebola outbreak in West Africa, the virus was thought to have a R0 value (measure of transmissibility) of approximately 1.51 to 2.53 whereas COVID-19 in 14 Italian cities has an R0 of 1.40 to 3.90 and experience from the SARS-CoV-1 pandemic shows that HCWs were disproportionately affected.13,14 This suggests that a tendency towards more aggressive and comprehensive PPE is not unreasonable from either an institutional perspective of protecting one's own workers nor from the broader pandemic response perspective of preserving these essential workers. We therefore feel that until further evidence is provided that such protections are not necessary, they should be implemented as quickly and cost-effectively as possible. We will now review a variety of strategies that can be used to bolster PPE supplies and effectiveness, organized first by type of protection then individual strategies.
Solicit Additional Resources
Respiratory and mucus membrane protection are essential components of workplace safety, and the global pandemic response has been hampered by shortages of N95 and comparable masks. Before the emergence of the SARS-Cov2 pandemic, China made 50% of the world's surgical masks, surgical gowns, and respirators such as N95s, while Taiwan made 20% of the Masks. As the epicenter of the SARS-Cov2 outbreak, China was in need of those masks to protect its healthcare workers, so they stopped exporting masks to other countries and rather imported them from other countries like Japan, the United States (US), and Europe. The spread of the COVID-19 pandemic around the world increased the demand for masks both in the United States and other countries, causing a shortage of essential respirators and surgical masks.15 1.5 billion N95s are produced yearly in the United States, but this quantity is insufficient to meet the increased demand. Public health modeling of a flu pandemic similar to SARS-Cov, suggests that US HCWs would need 1.7 to 3.5 billion respirators, surging to 2.6 to 4.3 billion as the pandemic progresses.16 The United States is not a stranger to shortages of essential medical supplies due to disasters. In 2017, Hurricane Maria struck Puerto Rico and devastated the island. Baxter, a medical supply company located in Puerto Rico is the largest intravenous (IV) fluid producer in the United States, supplying 50% of the saline used in US hospitals. The aftermath of hurricane Maria caused a shortage of saline for hospitals across the country.17 To address the shortage, other medical supply companies in the United States such as B. Braun invested $1 billion into opening several IV fluid manufacturing facilities in the continental United States.18 Recommendations to avoid PPE shortages in the future would be to increase respirators and surgical mask production in multiple countries (where feasible).
According to Occupational Health and Safety Administration (OSHA) regulations, each employer is required to develop a respiratory protection program, which includes “worksite specific programs” and respiratory equipment, as well as providing yearly mask fittings for these workers. According to the CDC, N95 respirators should be worn by HCWs when responding to any airborne infection and should be disposed of appropriately after each use. During a pandemic, reuse of N95 masks may be necessary to maintain supply and reduce shortages. Because of this, the CDC has therefore approved the decontamination and reuse of filtering facepiece respirators (FFR) as a crisis capacity strategy.19 Several methods are being investigated to determine the best ways to adequately decontaminate N95 masks and provide user safety. The three main decontamination methods being used are hydrogen peroxide vapor (HPV) or vaporous hydrogen peroxide (VHPTM, Battelle, Columbus, OH), ultraviolet germicidal irradiation (UVGI), and warm moist heat.
- 1. Hydrogen peroxide vapor (HPV) or vaporous hydrogen peroxide (VHPTM) uses wet H2O2 vapor or Dry H 2 O 2 vapor (for VHP)
- Decontamination parameters1-Initial conditioning phase of 10 minutes,2 gassing phase to saturate the room at 2 g/min for 15 minutes.3 Dwell phase or contact time at 0.5 g/min for 150 minutes.4 Aeration phase for off-gassing and breakdown of HPV into oxygen and water vapor for 300 minutes.
- Expected results-Effectiveness more than six log reduction.
- Mask Integrity-HPV exposure up to 50 cycles did not affect the inhalation resistance nor degrade the filtration media, it also did not affect the filtration efficiency as it was 99% for both inert and biological aerosol. The mask strap made out of elastic material began to show signs of degradation after 30 HPV cycles.20
- 2. Ultraviolet germicidal irradiation (UVGI)
- Decontamination parameters-UV-C irradiation minimum dose of more than or equal to 1 J/cm2/min at 254 nm peak wavelength for 1 minute in H1N1 influenza.
- Expected results-Effectiveness more than three log reduction.21
- Mask Integrity-UVGI treated N95 retains integrity of the respirator's fit and seal after 20 decontamination cycles.22
- 3. Warm Moist Heat
- Decontamination parameters-Temp 65 to 70 °C, relative humidity of 85 to 90 and processing time 30 minutes.
- Expected results - Effectiveness-more than four log reduction of viable H1N1 virus.23
- Mask Integrity-The integrity of the masks to withstand the decontamination process depends on the make and model of the N95 masks but trends showed that they were able to endure 10 decontamination cycles before showing damages.24
According to the National Institute for Occupational Safety and Health (NIOSH), respirators should be stored in a breathable container such as paper bags. Healthcare facilities should provide training to their staff and have clearly written procedures on how to store the individual respirators and masks as well as have written procedures on when to discard them. These storage methods would go into effect after aerosol generating procedures, contamination with blood, respiratory or nasal secretions, or other bodily fluids from patients, and following close contact with or exit from, the care area of any patient coinfected with an infectious disease requiring contact precautions.25
Alternate Options to N95s
Elastomeric masks—healthcare facilities in the United States are familiar with the use of disposable N95s and PAPRs as protective respiratory devices. One other device that is rarely used in a healthcare setting but has the potential of filling in supply gaps during a N95 shortage, is the reusable Elastomeric respirator which comes in full facepiece and half mask models.26 The benefits of using elastomeric respirators as an alternative to N95 include equivalent or higher assigned protection factor (APF), reusability, and low cost. Respirators have an APF (established by OSHA) which is “the workplace level of respiratory protection that a respirator or class of respirators is expected to provide to employees when the employer implements a continuing, effective respiratory protection program as specified by this section.” Elastomeric half-facepiece respirators (EHFR) has an APF of 10, which is the same to that of N95 and the Full facepiece (Elastomeric) has an APF of 50.27 Elastomeric respirators are usually made out of rubber or a synthetic material that can be easily cleaned and disinfected, durable, and provide the user with an effective face seal that is maintained with repeated cleaning and use. “The effectiveness of a respirator depends on three interrelated factors: the proper use of the respirator by the user (compliance), the respirator's fit and leakage during use, and the filter's performance.28
The low cost of EHFR makes them a reasonable alternative when there is a N95 shortage, as can be seen in Table 1. Current challenges with EHFR include interference with visual and speech intelligibility while the user has the mask on. Another challenge is the cleaning and disinfecting process. The best practices for disinfecting an EHFR are not fully established and require more research on certain characteristics, such as cleaning and disinfecting material, frequency of cleaning, duration of filter cartridge use, and exposed filter use.28
TABLE 1 -
Shows 3 Types of Respirators and Cost/Unit
||$25–$50/unit plus $2.50/3 set of filters/respiratory26
||$500–$800/unit with additional cost of three sets of filters/PAPR: $25/set, 1 battery per every 10 hrs of use: $250/rechargeable battery, three additional hoods per PAPR: $30/hood, three additional tubes per PAPR: $30/tube.26
EHFR, elastomeric half-facepiece respirators; PAPRs, powered air-purifying respirators.
During the N95 mask shortages, the use of internationally approved masks that met CDC requirements and approval were recommended for use for the public. However, the internationally approved masks were not approved by NIOSH and were therefore not recommended for use by HCWs.29 These include P2, P3 (Australia/New Zealand), PFF2 and PFF3 (Brazil), KN95, KP95, KN100, KP100 (China), FFP2, FFP3 (Europe), N95, P95, R95, N99, P99, R99, N100, P100, R100 (Mexico) DS/DL2, DS/DL3 (Japan), Korea 1st class (Korea).30
A PAPR is an integrated HEPA filter, fan unit, and facepiece which generates purified, positive pressure air for the user to breathe. It has been recommended as an adjunct to filtering facepiece respirators since 2003 because a HEPA filter has a filter efficiency of at least 99.97% of airborne particles (as opposed to 95% for the more common N95 filtering facepiece respirators). PAPRs are recommended for HCW use during the highest risk aerosol-generating procedures. Note however, that 100 level filtering facepiece respirators and elastomeric masks share the same minimum filtering threshold of 99.97% efficiency as HEPA filters. PAPRs include many features that are noteworthy with respect to a SARS-CoV-2 response. PAPRs do not require mask fit testing as FFRs do because they are loose fitting around the face and use continuous positive pressure to supply purified air to the facepiece while preventing inspiration of contaminated area. They therefore do not require the lead time of fit testing FFRs and can be implemented quickly with just-in-time training programs. They can also be used by HCWs who have failed FFR fit testing, potentially restoring critical staff to operational readiness. Additionally, PAPRs generally have decreased work of breathing relative to FFRs, since the user does not have to generate negative inspiratory pressure to facilitate the filtering action, nor does the user have to generate the positive pressure that is necessary to open the one-way exhalation valve present in most elastomeric masks. Similarly, they are less prone to condensation or moisture build up within the mask which can cause significant user discomfort with FFRs and elastomeric and discourage compliance. Finally, PAPRs can be disinfected multiple times across multiple users.
Some of the challenges with PAPRs are expense, dependence on battery power, and the barrier to verbal communication. PAPRs are significantly more expensive than other methods of respiratory protection. A typical PAPR package with blower unit, filter, facemask, battery, and charger can cost approximately $1500, roughly equivalent to the cost of 1000 to 2000 N95s or 30 to 60 elastomeric respirators. If this is beyond the budget of a healthcare facility, equipping selected staff with 100 level elastomeric respirators would be a reasonable and cost-effective alternative. Because PAPRs are powered units, their effective use is limited by the discharge time of their batteries which can last 4 to 6 hours for the least robust units or up to 8 to 12 for the most powerful. It should be noted that most users would likely not tolerate the full duration of these batteries due to physiologic needs, and for some, the claustrophobic nature of the mask. Motor and air noise can be a barrier to effective communication by impairing the hearing of the PAPR user as well as the ability of others to hear the user. This is particularly acute for hood type face covers as opposed to full facepiece masks. This can be worrisome since the use of the PAPR typically implies that a critical aerosol generating procedure is occurring nearby, that is, a time when effective communication is likely to be even more important than usual. Finally, the introduction of PAPRs into a workplace will require usage logs, tracking of filter lifespans, maintenance of a constant supply of charged batteries, and routine maintenance posing additional logistical challenges.
Studies have shown that asymptomatic people can still transmit SARS-CoV-2 unknowingly to their family members and others in the community. It is with this knowledge that the CDC recommended the wearing of home-made cloth face masks to the public as a strategy to reduce community-based transmission. These home-made masks are not to replace surgical masks or N95 respirators for HCWs therefore, they are not recommended for use in a healthcare setting.31 The need to educate the public about the correct procedure of donning and doffing home-made masks is important, as the effectiveness of these masks relies on the person's ability to wear them correctly. This is why the CDC has given guidelines and educational tutorials on wearing and making home-made cloth face masks and they also recommend washing the homemade cloth masks in the washing machine with hot water and detergent and drying it hot in the dryer.32
Studies have shown that mucous membranes (MMs) including the eyes, nose, and mouth are routes of viral infection including SARS-CoV-2 and therefore require protection with PPE. Splash proof or resistant goggles are appropriate any time there is contact with splashes of potentially infected body fluids, including the nasopharyngeal or expectorated sections of COVID-19 patients. Full face shields serve a similar role in protecting mucus membranes but also have the added benefits of protecting the HCWs face from contamination (which could lead to secondary introduction into MMs) and prevent gross contamination of valuable respiratory PPE. If N95s or the filter portion of elastomeric masks becomes grossly contaminated with body fluids, disinfection should not be attempted, and they should be disposed of instead. While serving similar functions, it is common practice to wear face shields and goggles together for added protection.
According to CDC guidelines, cleaning of reusable face shields or goggles should be done by using a clean cloth saturated with neutral detergent solution and cleaner wipe. A clean cloth and EPA-registered hospital disinfectant solution should be used to clean the inside of the face shield or goggles followed by wiping the outside of the face shield or goggles and followed by a second cleaning with alcohol to remove residue and air dry.33 When supplies are unavailable from conventional medical suppliers, non-medical manufacturers may be quickly adapted to produce face shields as was demonstrated by MIT's Project Manus.34
Hats and Headwear
Standard precautions do not specify any particular head coverings while working in situations with possible exposure to blood or other potentially infectious materials, and a superficial reading might therefore suggest that no coverings are required. However, we would caution against this approach, since SARS-CoV-2 has been shown to have persistence on a variety of surfaces and is spread by respiratory droplets. It therefore seems not only possible but likely that such droplets could contaminate the hair of HCWs and subsequently be spread further by contact to mucus membranes of the eyes, ears, nose, or mouth. We, therefore, hold the opinion that when exposure to SARS-CoV-2 droplets or aerosols are expected, HCWs should be required to wear water resistant head coverings. These could take the form of disposable surgical caps/bouffants, reusable surgical caps, of other reasonable caps at the HCWs preference as long as they are: water resistant, able to be appropriately laundered/disinfected, and able to be doffed safely and easily with minimal risk of contaminating the HCW person. Furthermore, if HCWs are wearing traditional scrubs shirts that are required to be pulled over the head, that these be removed before or concurrently with head coverings to prevent contamination with fomites from scrubs passing over the hair and/or that HCWs shower immediately after doffing to further reduce contamination.
For the purpose of this paper, we assume that HCWs are donning and doffing protective overgarments de novo between all patients in an undifferentiated setting in order to prevent cross-contamination. For patients triaged to lower risk areas, careful review and consideration should be conducted to determine if these patients can safely be cared for without contact precautions. For sufficiently high community incidence, it may be appropriate to treat all patients as potentially infectious regardless of symptoms and wear full protective overgarments continuously during all patient encounters.
Glove optimization strategies from the CDC are categorized by state of operations for which they are recommended: conventional, contingency, and crisis capacity. Conventional capacity—is defined as measures used in providing patients care without alterations to common daily practices and are used when medical supplies are adequate.35 These include the use of nonsterile disposable gloves according to the recommendations approved by the FDA and routine use of other elements of the hierarchy of control such as engineering and administrative control methods to reduce unnecessary usage of gloves.36
Contingency capacity is defined as temporary measures used during a time of shortages that alter the daily standard of practice but have no significant change in the delivery of care to a patient. These measures include, for example, use of gloves past their shelf life for training activities and use of gloves from other countries. Notably, the CDC does not require approved non-sterile gloves to have an expiration date, but most manufactures still include shelf life dates. Use of gloves from other countries, especially those identical to FDA approved gloves and which meet both United States and international standards such as the EN 455 from Europe, the AS/NZS 4011 (vinyl) from Australia, and the JIS T9107 from Japan can also be used if available.35
Crisis capacity—temporary measures that are not equivalent to the conventional standard of care, but which can be utilized during extreme shortages. These include the use of gloves past their designated shelf life for healthcare delivery, prioritizing disposable gloves, extended use, and use of non-healthcare glove alternatives. Prioritization of glove use is the conservation strategy of omitting gloves during routine patient care particularly with endemic pathogens (eg, MRSA and VRE) and reserving them only for situations where HCWs are anticipated to encounter blood or other potentially infectious materials. Extended wear of disposable medical gloves by HCW is also recommended by the CDC in which a HCW does not change their gloves when working with patients with the same confirmed infectious disease in a shared location. Instead they should sanitize their gloved hands with alcohol-based hand sanitizer, soap, and water or using diluted 10% to 13% bleach solution between patients to reduce cross contamination of other pathogens to other patients (use of diluted bleach should be the last resort because of its many logistical challenges). It is highly recommended that HCWs dispose of gloves that have been overtly contaminated with blood/other body fluids, damaged by tears or degradation, worn continuously for a maximum of 4 hours or previously doffed. Hand hygiene using alcohol-based hand sanitizer or washing with soap should always be done after glove removal. Other strategies used in crisis capacity include; non-sterile disposable gloves past their shelf life can be used by HCWs to deliver medical care to a patient with the exception of surgical and sterile procedures. Prioritization of non-sterile gloves use such as limiting the use of gloves to only procedures that require contact with blood or other bodily fluids. Finally, the CDC recommends the use of alternatives such as non-healthcare gloves from other industries during crisis situations, but only when contact with pathogens is not expected.35 We agree with this recommendation in principle, but would also clarify that in true crisis situations and only as a last resort, we recommend any waterproof, nonporous gloves could be used, even in the circumstances of HCW/pathogen contact.
Overgarments for the purpose of contact precaution PPE can come in the form of gowns or coveralls. The CDC offers no general preference for one over the other, and selection between the two is context dependent. Gowns are worn over some other base-layer such as scrubs. Coveralls of course can provide neck to ankle protection, sometimes including foot and head coverings and ideally, should include a flap over their closure to prevent liquid penetration. Coveralls can serve either as an overgarment over a base-layer, or as a base with gown overlaid. If coveralls are used as an overgarment, it would typically be changed between patients to prevent cross-contamination. In the authors’ experience, this overgarment approach has been most commonly seen in prehospital context when HCWs need to be highly mobile for patient retrieval and transport, and typically have a single longitudinal patient contact that has a definitive endpoint upon arrival to the hospital. At healthcare facilities, HCWs often move back and forth between multiple patients over the course of a shift which can make coveralls an undesirable option for multiple reasons: potential for cross-contamination, increased donning/doffing time, and increased expense, since these coveralls are disposable and not easily laundered. Furthermore, since healthcare-use coveralls are disposable they will be vulnerable to shortage and supply chain disruption as will be discussed below. The foremost strength of coveralls is the comprehensive contact precaution that they can provide which may be of benefit for use as a base layer in high exposure settings such as dedicated COVID-19 wards.37
Gowns are the most prevalent solution to contact precaution PPE within health facilities and are generally easier to use and more versatile than coveralls. However, several problems are common to all types of protective gowns: donning and doffing inherently adds time to the patient care process which can be frustrating to HCWs accustomed to a typical workflow, especially in high volume and high acuity settings. This can lead to HCW perceptions that “we are not moving fast enough” or “we are not getting enough done.” These frustrations can then lead to poor compliance and ultimately put workers’ health at risk. Other challenges common to all types of gowns include ineffective use: for example, not using all of the provide fasteners to close the gowns (especially if gowns have more than one tie that is difficult to access on the back of the gown by a lone HCW) which can leave areas of the body unprotected and not fitting tie closures tightly enough, especially for collar ties which can leave the neckline exposed to contamination. Finally, most gowns are “one size fits all” which can result in HCWs at either extreme of height/weight being inadequately protected. Particularly tall workers may find that gowns do not adequately protect their wrists due to short sleeves. Particularly short workers may find that excessive length may result in decreased dexterity or increased risk of inadvertent contact with other objects, increasing the risk of accidental contamination.37
Some strengths and weaknesses are unique to disposable and reusable gowns and selection between these should be carefully considered. Disposable gowns are often designed with a “tear-away” doffing method which is easier for solitary HCWs. Previous experience from Ebola outbreaks has shown that the doffing process can be a particularly high-risk time, and the importance of facilitating this process safely cannot be understated.38 However, these safe tear-away features can also be liabilities while donning and providing patient care since premature tearing can leave the worker exposed. Finally, their disposable nature is an inherent risk during a pandemic as global supply lines are vulnerable to compromise worsened still by the increase in global demand.37
In contrast, the reusability of some gowns is a feature which is desirable during a pandemic. If a healthcare facility is willing and able to establish a pre-existing stockpile of equipment for a future pandemic, the quantity of gowns needed in the stockpile will be considerably smaller for reusable gowns versus disposable. If sufficient quantity is acquired in advance to maintain use, stock, and disinfection throughput, then such gowns are proof against the shortages that have been reported in early 2020. Reusable gowns generally use rear-facing tie fasteners which can be more difficult for HCWs to doff unassisted. Because these ties are cloth, they cannot be ripped or broken to release the worker and if they become knotted, it can become a serious challenge, requiring assistance from another worker. Finally, reusable gowns generate a contaminated waste stream that requires ongoing worker contact to launder and disinfect which does pose a risk for worker exposure.
While OSHA current guidelines prohibit home laundering of personal protective apparel or equipment, there are exceptions to this recommendation such as uniforms and scrubs (except when they are contaminated with blood or infectious material).39 After a 12-hour shift, most HCW are ready to go home and relax, and some change into casual wear in the changing room provided in the hospital, while others decide to wear their scrubs home. According to a study that researched surrogate bacteriophage (Phi 6, enveloped dsRNA virus and MS2 positive-sense single-stranded RNA) contamination that occurs during doffing of PPE, the surrogate bacteriophages were detected on 10% and 20% respectively on scrubs of HCWs.40 This brings into question the level of undergarments exposure to infectious agents during doffing of PPE. With the COVID-19 pandemic and high number of HCW being infected with the virus, it might be time to recommend that healthcare facilities develop just in time training or SOPs on how to properly doff scrubs after doffing PPE. Other recommendations include redesigning scrubs to have zippers or buttons so that HCW can easily doff them. Laundering HCW scrubs could be beneficial for healthcare facilities and this would ensure proper cleaning of scrubs worn in the hospital and most importantly, it would limit the spread of infectious agents outside the hospital.
At time of writing, we could not identify any specific recommendations or guidelines with respect to shoe coverings for SARS-CoV-2. However, since SARS-CoV-2 has been shown to be persistent on surfaces and is potentially transmissible by fomites (especially after being widely dispersed in a room by droplets or aerosols), it seems prudent to consider additional precautions with respect to footwear. These might include temporary shoe coverings that can be applied prior to shifts and then discarded at the conclusion. Requiring or recommending that employees have dedicated shoes for their clinical work (and are always assumed to be potentially contaminated) and change prior to departure or having a shoe decontamination procedure as was seen during the Ebola responses, is prudent. For example, a footwear policy might include the use of non-porous shoes and waterproof boots (synthetic boots or clogs) that must be worn at all times during the clinical shift, and decontaminated at end-of-shift with either disinfecting wipes, sprays, or by walking through a decontamination pool of sodium hypochlorite or chlorine dioxide solution. The policy will include on-site storage of the boots either in an appropriate changing area or locker room while not in use. Rain boots are relatively low cost, highly durable, and extensively reusable unlike disposable shoe covers that constantly need replenishment, and potentially generate hazardous waste streams. Such a policy, although non-traditional when compared with routine practices in ERs or OR settings, has considerable utility. Other improvised solutions such as plastic basins or “kiddie pools” can also be used for shoe or outerwear decontamination procedures; leaving the disinfecting solution itself as the only consumable for the procedure. Such procedures may have an unpalatable upfront cost for limited or sporadic outbreaks but may be a useful tool in high-intensity or prolonged pandemic responses.
Despite prior experience with SARS-CoV-1, providing optimal personal protective equipment to all healthcare workers has been an elusive goal in practice. However, through this review we have identified key considerations and points of failure. Due to the nature of the pandemic, conventional PPE may be unavailable due to cost, availability or supply chain disruption. In such cases, pragmatic alternatives should be carefully considered with a return to basic principles of infection control. These solutions can come in the form of off-the-shelf consumer products repurposed for healthcare use, or equipment from other industries that meet the same minimum standards for protection. Finally, although PPE has recently received considerable attention due to national shortages, process and system changes should be the primary tools to prevent unnecessary hazards to HCWs and PPE waste. Eliminating or containing hazards and reducing the number of workers exposed are the most effective strategy.