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Personal Protective Equipment (PPE) and COVID-19

By Currents Editor posted 04-09-2020 09:25


The ongoing pandemic of Coronavirus Disease 2019 (COVID-19) is unprecedented in scale, with devastating effects seen in the economic and social spheres of society. The World Health Organization (WHO) declared COVID-19 a pandemic on March 11, 2020, after the number of cases outside of China skyrocketed 13-fold since late February. 

The micro-organism causative of COVID-19 infection is a β-Coronavirus, an enveloped positive sense single-stranded RNA virus, which shares the same family as severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) and Middle Eastern respiratory syndrome coronavirus (MERS-CoV) [1]. COVID-19 is also known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) given its similarities to SARS-CoV-1 regarding genetics and mechanism of transmission. These species of coronaviruses have been implicated in the current and past major outbreaks with a shared mechanism of transmission of person-to-person droplets or contact with contaminated surfaces. 

Disease severity ranges from a patient being asymptomatic to severe symptoms, such as dyspnea that can progress into respiratory failure and eventually septic shock or multiorgan system dysfunction. Incubation time ranges from 2 days to about 2 weeks, which makes the transmission of the disease difficult to control given high chances of transmission from asymptomatic or mildly symptomatic patients. 

Mode of Transmission

COVID-19 is spread through respiratory droplets produced when an infected individual coughs or sneezes, with person-to-person transmission most commonly occurring with close or protracted contact. Initial studies demonstrated the stability of the COVID-19 droplets, leading to the working understanding that this virus can be spread through aerosolization and fomite transmission. This virus may stay airborne for up to 3 hours with the majority of the droplets falling a short distance to the ground. COVID-19 may remain viable upon cardboard up to 24 hours and about 2-3 days on plastic and stainless steel surfaces. 

On March 10, 2020, the Centers for Disease Control and Prevention (CDC) released an interim guidance report for the prevention and control of confirmed or suspected COVID-19. Part of this report discusses the appropriate precautions healthcare workers should take, including appropriate hand hygiene before and after contact with the patient, as well as the appropriate types and use of PPE. The following sections discuss the various types of masks available in the United States and their appropriate use. 

               PPE Guidance for Healthcare Workers Caring for PUI/ COVID-19 Patients


1. Patient on Ventilator

2. During Aerosol generating procedures

All other inpatient settings



Surgical mask

Contact protection

Gown, goggles

Gown, goggles

Eye protection

Face shield/ goggles

Face shield/ goggles

Aerosol generating procedures: suctioning, intubation/extubations, BiPAP/CPAP, bronchoscopy, endoscopy, GI tract suctioning, nebulizer treatment 

Eye Protection

Eye protection is a necessity, as the epithelia ocular system eye represents an additional mucosal surface that can be exposed to viral infectious aerosols and contaminated fomites. Additionally, the nasolacrimal system may deliver viral particles directly to the nasopharynx. Thus, personal eyeglasses and contact lenses are not adequate eye protection. Sufficient PPE would comprise goggles or a disposable face shield to be donned prior to entering a patient care area, and doffed upon leaving said area. 


Given the viability of COVID-19 on several surfaces, gowns are protective against surface contamination and standard droplet precautions apply. Gowns are also to be donned prior to entering patient care areas, and doffed and discarded in a dedicated container prior to leaving.  

Surgical Masks

Surgical masks are used to protect the wearer from gross hazards, such as blood and body fluids, and to prevent the wearer from spreading potential microorganisms to others. However, they do not prevent the wearer from inhaling airborne particles and do not have the tight face seal respirator masks provide. 


A respirator is a device designed to protect the wearer from inhaling airborne microorganisms, particulate contaminants, and hazardous fumes and gases. Airborne micro-organisms can travel via small respiratory droplets that become aerosolized when an infected person sneezes or coughs, or when aerosol generating procedures are performed, such as intubation. Given the rapid global progression of COVID-19, it is crucial for providers to have the proper knowledge regarding the various types of respirators and their appropriate use. At this current time, the CDC recommends that healthcare professionals don appropriate PPE while working in a healthcare facility and recommends against the general public use of respirators.

p_guy.pngRespirators come in various sizes and models and must be appropriately fitted for an individual’s face and provide a tight seal per guidelines from the U.S. National Institute for Occupational Safety and Health (NIOSH). The NIOSH air filtration rating is the standard classification of filtering respirators. The first part of the filter's classification uses the letters N, R and P to indicate the resistance to filter efficiency degradation; N stands for not resistant to oil, R stands for resistant to oil, and P stands for oil proof and used when said filter is needed for longer than one work shift. Masks are also divided into different filter efficiencies of 95%, 99% and 99.97%, indicating the percentage of particles that are removed from the air. 

Powered Air Purifying Respirator

Powered air purifying respirators (PARPs) utilize a motor to pull air through the intake into filter canisters, thus decreasing the necessary work of breathing for the wearer. These devices accommodate a looser fitting hood, foregoing the need for fit testing, which may be single or multiple use. The protection conferred varies by the type of filter employed. PAPRs offer the flexibility of allowing reuse during a prolonged event. These devices are commercially available by companies such as 3M, Grainger, Trend and Bullard.

N95 Respirators

mask.pngThe N95 is approved for at least 95 percent filtration efficiency against non-oil-based particles about 0.3 micron in size. The edges of the respirator are designed to form a seal around the nose and mouth. 

In the setting of the COVID-19 pandemic, institutes are reusing N95 masks if they have been covered with a surgical mask (ie, protected from surface viral contamination). The surgical mask used to cover an N95 mask during a patient encounter is to be discarded when the masks are removed. Surgical masks are not reused after wearing them to care for a COVID-19 PUI. They should be removed and discarded prior to exiting the PUI room.


N95 Respirator

Surgical Mask


Against small particle aerosols and large droplets

Against large droplets, splashes or sprays of bodily


Filters out at least 95% of airborne particles including large and small particles

Does not provide the wearer with a reliable level of protection from inhaling smaller airborne particles and is not considered respiratory protection


National Institute for Occupational Safety and Health (NIOSH)

U.S. Food and Drug Administration (FDA)


Minimal leakage

Not fit tested; leakage


Fit testing required

No fit testing required


Sterilization: LightStrike™ Germ-Zapping™ Robots and Disinfection Pod

pod_1.pngSARS-CoV-2 reported to be infectious up to 2-3 days on plastic and stainless steel, so sterilization of hospitals, laboratories and nursing homes becomes a challenge. Despite the appropriate use of PPE, it is vital for healthcare facilities to enforce proper sterilization techniques to reduce fomite transmission of COVID-19. 

Pulsed xenon ultraviolet (PX-UV) is increasingly being used to disinfect patient rooms, operating rooms and other areas of hospitals.

Xenex’s LightStrike Germ-Zapping Robots use pulsed xenon, an inert gas that is environmentally friendly, to create ultraviolet light that destroys bacteria, viruses, fungus and spores on hospital surfaces. Pulsed xenon (PX) ultraviolet (PX-UV) devices have been linked to a reduction in hospital-acquired infection rates of more than 50%, such as MRSA, VRE and C. difficile. The LightStrike™ disinfection technology has been tested against the MERS coronavirus. In a study published by Stibich et al (2016), PX-UV demonstrated a reduction in the MERS coronavirus after a 5-minute disinfection cycle. As such, Xenex standard protocols are sufficient and longer cycle times are not needed. 

pod_2.pngIn addition, PX-UV has been demonstrated reduce colony amounts of MERS-CoV, though these were done as liquid suspensions, which reduced exposure and UV light penetration, limiting the logarithmic reduction achieved. Utilizing the LightStrike™ Robot before and after manual cleaning would likely contribute to reducing the risk of transmission to healthcare workers while using appropriate PPE.

LightStrike Disinfection Pod™ is a mobile disinfection pod to aid hospitals in disinfecting high-touch complex equipment such as ventilators, ultrasound machines, vital sign monitors, wheelchairs and mobile workstations. The disinfection pod uses reflective material to ensure 360-degree coverage of UV light to sterilize the equipment. The unit is designed to adapt to the hospital environment, as it can be easily set up by a single user and folded away without impeding daily workflow.  


  1. Li Q, Guan X, Wu P, Wang.Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus Infected Pneumonia. N Engl J Med. 2020 Jan 29. doi: 10.1056/NEJMoa2001316. [Epub ahead of print] PubMed PMID: 31995857.
  2. Wu Z, McGoogan JM. Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China: Summary of a Report of 72 314 Cases From the Chinese Center for Disease Control and Prevention. JAMA. 2020 Feb 24. doi: 10.1001/jama.2020.2648. [Epub ahead of print] PubMed PMID: 32091533
  3. Belser JA, Rota PA, Tumpey TM. Ocular tropism of respiratory viruses. Microbiol Mol Biol Rev. 2013;77(1):144–156. doi:10.1128/MMBR.00058-12
  4. Simmons, Sarah & Morgan, Melissa & Hopkins, Teresa & Helsabeck, Kim & Stachowiak, Julie & Stibich, Mark. (2013). Impact of a multi-hospital intervention utilising screening, hand hygiene education and pulsed xenon ultraviolet (PX-UV) on the rate of hospital associated meticillin resistant Staphylococcus aureus infection. Journal of Infection Prevention. 14. 172-174. 10.1177/1757177413490813.
  8. The microbiological impact of pulsed xenon ultraviolet disinfection on resistant bacteria, bacterial spore and fungi and viruses. Mark Stibich,1* Julie Stachowiak
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