Infrastructure Guidance for COVID-19/COVID-19 Infection Prevention and Control

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Infection prevention and control for COVID-19

Infection prevention and control in the context of Covid-19 should focus on three pillars: exposure reduction by workflow, cleaning disinfection and decontamination, and use of personal protective equipment.

General Concern:

Contact and droplet spread

Transmission of SARS-CoV-2 virus occurs via contact and droplet spread. The virus has been shown to persist on surfaces for extended periods of time and is known to be efficient at infecting people.

Waste products: As SARS-CoV-2 is carried in body fluids and fecal matter, disposal of contaminated items (tissues) and cleaning regimes (spaces, garments, linen) should be accommodated carefully in the workflow design and infrastructure provision.

Limited Concern:

Water and Sewerage Contamination

The International Water Association (Link to Report) concluded that water and sewerage contamination is not considered to be a key risk factor for Covid-19. The panel expressed concern for how waste and specifically wastewater (medical) would be handled by places (e.g., hostels, hotels) that are used to serve as interim Covid-19 quarantine or testing facilities or accommodation. These are places other than hospitals that are used in the interim for such purposes and do not usually handle medical wastewater. Such facilities should be monitored carefully.

Airborne Transmission

Under exceptional circumstances, where the risk of airborne transmission arises the following should be considered. Where aerosolising activities have a potential of contaminating occupied spaces with partially diluted or undiluted contaminated air, or where this is indeterminate, aerosolising activities should be designated to an alternate area. In the event that an alternative is not available, some treatment regime (air filtration or air disinfection) may be necessary.

As SARS-CoV-2 is not considered airborne, general respiratory protection against airborne transmission is not considered necessary, except where aerosolisation of particles may be likely. The following procedures have been identified as having the potential for liberating infectious aerosols.

• tracheal intubation,
• non-invasive ventilation,
• tracheotomy,
• cardiopulmonary resuscitation,
• manual ventilation before intubation and bronchoscopy
• diagnostic sampling as patients can be induced to cough and sneeze

Administrative controls

Site Layout

ACS will accommodate a variety of clinical, logistical, support and auxiliary services associated with the render of care. Functions to be accommodated are:

Clinical services

Triage, rapid assessment of persons entering the facility, to expeditiously identify and render the appropriate service.

• Inpatient accommodation organised according to cohorting principles, discussed below.
• Testing and diagnostics, including laboratories and x-ray.

Logistical

Staff entry, preparations to transition from outside to clinical work environment, including pause areas for relief.

• Emergency services, visitors
• Goods, supplies and storage
• Waste removal

Support services

Support services key to the provision of clinical services should be separated, so that the risks and associated with that particular activity can be managed. Support services are:

• Kitchen
• Laundry
• Mortuary

Support services can be provided off-site, in which case safe, secure and efficient transfer and logistical arrangements should be designed.

Auxiliary services may be provided on or near the ACS site. This included overnight accommodation for staff who may not wish to return home to avoid exposing their families, or who need rest between shifts, or for discharged patients awaiting transport home, volunteers who have recovered from SARS-CoV-2. Limited psychosocial services and allied health services may also be provided on or near ACS for example by approved NGOs.

Spatial configuration and layout can ensure unnecessary cross-over of function is avoided. This entails systematic separation of functions and managed transition between activities to facilitate consistency of care, an orderly, efficient work environment, less waste and reduced risk for improved outcomes. To achieve this, functional relationships should first be considered at the site level before being considered at the unit level.

Personal Protective Equipment

Respiratory Protective Equipment

Filtering facepiece respirators (FFR), are subject to various regulatory standards around the world. These standards specify certain required physical properties and performance characteristics in order for respirators to claim compliance with the particular standard. During pandemic or emergency situations, health authorities often reference these standards when making respirator recommendations. N95 masks alone and FFP2s with fluid shields are recommended for use by healthcare workers operating in high-risk COVID-19 settings. FFP2 and N95 masks filter at least 94% of a challenge aerosol with a mean mass diameter of between 0.3 and 0.4 microns. This filtration range includes the new coronavirus.

Emergency use recommendations

Hospitals across South Africa are running out of N95 respirators are tested and certified by the National Institute for Occupational Safety and Health, or NIOSH, a research agency that is part of the Centers for Disease Control and Prevention (CDC). In response to continued respirator shortages, the U.S Food and Drug Administration (FDA) issued an emergency use authorization for KN95 masks. Regulated by the Chinese government, these are almost identical in performance to N95 masks. There are slight differences in their specifications, like a variation in the maximum pressure the masks must be able to withstand as a person inhales and exhales. In South Africa, FFRs are promulgated under South African National Standard SANS 1866-2 and regulated under the compulsory specification VC8072. While in South Africa KN95 respirators were already in use since the Covid-19 outbreak, there were no specific guidelines on which criteria to be met in order to use the product, including evidence demonstrating that the respirator is authentic. In addition, there is conflicting guidance over the application of these respiratory masks.

N95 and FFP2 respirators have been considered the preferred type of respirators in South African healthcare settings. These respirators are a crucial piece of equipment for healthcare workers treating coronavirus-infected patients in some countries. In response to the limited supply of N95 respirators, KN95 arose as an alternative. However, there are many questions about the quality and effectiveness of the similarly named KN95 respirators which originates from China. In its current guidance, the SANS 1866 pt. 2 has set out a specification that the N95 and FFP range of respirators should meet.

Before adopting the use of KN95s in South Africa, there is an urgent need to address the challenges in determining the authenticity of KN95 that are currently being used in SA settings in order to avoid fraudulent products being identified as KN95s making their way into healthcare settings. Until those challenges are addressed, KN95s should be used with extreme prejudice.

*While respirators equivalent to FFP2/N95 are not available, the use of surgical masks with visors is an acceptable interim alternative to FFR

Environmental Controls

Ventilation

SARS-CoV-2 is understood to be primarily droplet spread, with droplet protection measures such as cough hygiene, distancing and face masks being the most effective measures for infection control. Ventilation is understood to be an ineffective intervention for reducing the risk of close-range droplet transmission.

Special conditions are known to exist which can extend the range of droplet spread. These settings have conditions in common which extend the capacity or range of the source and include spaces which:

• are overcrowded with stagnant air
• have increased droplet generation rates.

Examples of spaces with increased droplet generation rates include clinical spaces where operational processes can promote the aerosolisation of infectious droplets.

• ICUs and procedure rooms for:
  • Endotracheal intubation
  • Bronchoscopy
  • Non-invasive ventilation
  • Tracheostomy
  • Manual ventilation before intubation
  • Cardiopulmonary resuscitation
• Surgery rooms
• Lavatories

Higher than normal droplet generation rates increase the probability of far range transmission. Engineering controls appropriate for far-field transmission is indicated for these spaces but not indicated for general spaces.

The observation that increased transmission occurs in under-ventilated and overcrowded spaces does not indicate higher than normal ventilation rates, but rather avoiding under-ventilated spaces.

Additional context and information and can be found in Ventilation and COVID-19

Ultraviolet Surface Disinfection for SARS-CoV-2

•For general guidance on UVGI for surface decontamination, refer to Surface Decontamination by Ultraviolet Germicidal Irradiation
•For general guidance on UVGI for air disinfection, refer to Infection Prevention and Control/Air Disinfection

There is good reason to expect that SARS-CoV-2 will be susceptible to UV-C. UV-C, when applied at the correct dose as it has been found effective against influenza viruses including human coronavirus (SARS-CoV-1).

According to Kowalski et. al. , Covid-19 is susceptible to existing disinfection methods such as chemicals and exposure to ultraviolet radiation in the electromagnetic range ~ 200 – 280nm (UV-C) because of the similarity of its structure to other susceptible coronaviruses such as SARS-CoV-1 and MERS.

As SARS-CoV-2 is recent and novel, UVGI efficacy has not yet been conclusively established against this particular pathogen. For the reasons stated above, UVGI – the exposure of potentially contaminated contact surfaces to UV-C is identified as a measure with good prospects to reduce and delay occupational exposure of healthcare and transport services workers, as well as their clientele, and to contribute to the strategy of “flattening the curve”.

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UV-C air disinfection was been explored extensively in the context of TB infection prevention and control by the South African scientific community in association with international experts. National Technical Standards, Protocols, guidelines and testing capacity for application of upper-room UVGI in airborne transmission have been established. This experience has provided important basic knowledge and key insights into the underpinning science and theory as well as application constraints, albeit for a different application.

The coronavirus, SARSs-CoV-2, is understood to be transmitted primarily by contact and droplet spread, is highly contagious and spreads more rapidly than its predecessors Severe Acute Respiratory Syndrome (SARS-Cov-1) and Middle East Respiratory Syndrome (MERS)</ref>, so any residual surface contamination can pose a public health threat. COVID-19 transmission remains controversial as researchers across the globe remain conflicted about droplet and airborne as modes of transmission. Clarifying the transmission routes and survival of viruses on frequently used surfaces is essential for containment of the outbreak. Research has successfully demonstrated that the virus has the potential to be aerosolised, and therefore can theoretically opportunistically transmit through the airborne route, it is understood that, except in aerosolising procedures, risk of coronavirus transmission via the airborne route is low. Similarly, risk via water and wastewater is low . Persistence of the virus on a variety of surfaces has been demonstrated , underpinning concern that SARS-CoV-2 may be transmitted from infected (even asymptomatic) persons to others from touching common surfaces, even after the infector has departed for several hours . Efforts to contain the coronavirus, to stem the pandemic, should therefore primarily focus on contact and droplet transmission. Contact and droplet transmission is of concern in public transport systems taxis which convey very large transient populations is normally congested conditions, such as in trains and mini-bus taxis. Transfer of suspected or confirmed Covid-19 patients in planned transport or emergency service vehicles poses a risk since studies show that conventional decontamination procedures may be inadequat. In a pandemic, and within already constrained congregate settings found in infrastructure, such as clinics, hospitals, prisons, schools and transport hubs, overcrowding and close proximity of infectious and susceptible individuals could create conditions which amplify the risk of Covid-19 transmission.

In the South African context, the reduction of exposure to Covid-19 is a priority, in order to:

• reduce and delay occupational exposure of frontline workers especially healthcare and transport services workers;
• reduce exposure to public health risk, especially to the most vulnerable, such as PLHIV and persons with TB who are the principal users of public transport;
• contribute to the strategy of “flattening the curve”; and
• preserve and protect the healthcare service so as to ensure continued service.

This guide proposes UV-C surface disinfection for reducing contact and droplet transmission of SARS-CoV-2 through the following applications:

1. Portable disinfection devices for use in the transport sector (minibus taxis, trains and emergency and planned patient transport)
2. Public Spaces
3. Commercial and industrial occupational settings
4. Decontamination of personal and respiratory protection equipment

UVGI Efficacy for SARS-CoV-2

Insufficient laboratory trials are available to use in developing a dedicated surface UVGI dosing guide for SARS-CoV-2. As SARS-CoV-2 has shown similar environmental survival rates to the SARS-CoV-1 virus, it is proposed that SARS-CoV-1 UVGI efficacy data be used

UVGI dose

The UV-C dose required to achieve a particular pathogen reduction rate is calculated from the single-stage decay equation:

S=e-kD

where:

• S is the Survival fractional [%]
  
• k is the UVGI rate constant [m2/J]
  
• D is the UVGI exposure dose [J/m2]
  

In the absence of a specific UVGI rate constant for SARS-CoV-2, Kowalski et. al. have proposed an average value for the calculation of the required dose. The average rate constant from recent Coronavirus studies is shown in the table below.

Summary of Recent Ultraviolet Studies on SARs Coronavirus

Microbe	D90 Dose J/m2 (J/cm2)	Uv k [m2/J]
SARS Coronavirus CoV-P9	40 (0.04)	0.05750
SARS Coronavirus (Hanoi)	134 (0.134)	0.01720
SARS Coronavirus (Urbani)	241 (0.241)	0.00955
Average	138 (0.138)	0.02808

The required UVGI dose for SARS-CoV-2 for a 4 log reduction (99.99% pathogen reduction rate) is calculated by expressing the single-stage decay equation as follows:

ln(⁡S)=-k·D·ln(⁡e)	

∴D = ln ⁡0.0001/(-0.02828) = 328 mJ/cm2 	  =(0.328 J/cm2)

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