In order to prevent the spread of COVID-19, the Department of Health (DOH) Center for Disease Control (CDC), European Centre for Disease Control (ECDC) and World Health Organization (WHO) have prepared recommendations that continue to be updated. This advice is based on the information available on the 7th April 2020.
Infection control and COVID-19
The COVID-19 virus is transmitted between people through close contact and droplets, but not by airborne transmission. The people most at risk are those who are in direct contact with COVID-19 patients. It is important to remember to wash your hands frequently for at least 20 seconds, to exercise social distancing (minimum 1.5m) and practise respiratory hygiene (cough and sneeze into your elbow or tissue that is disposed of immediately). The avoidance of touching your eyes, nose and mouth is an essential measure to prevent transmission (see breakout box below).
Administrative, environmental and engineering controls provide an important method of infection control with PPE as the last line of defense. Engineering controls include the use of shields on equipment that require close contact, such as slit lamps, to reduce exposure. Administrative controls may include limiting paths of entry to clinics, practices, optical stores, installing physical barriers and the establishment of triage stations to screen patients outside the facility. Health care workers caring for COVID-19 patients should be provided with appropriate personal protective equipment (PPE) and be trained in its use. This includes appropriate methods of putting the equipment on and taking it off.(1). Appropriate disinfection or disposal of PPE after use is also important.
Personal protective equipment guidance
The current guidance for PPE from WHO (2) has several categories depending on the level of risk. The focus is on contact and droplet precautions to prevent exposure of the nose, eyes and mouth. The PPE required, for example, during hospital care of COVID-19 patients includes gowns, gloves, medical masks and eye protection (goggles or face shield). For aerosol-generating procedures specifically (e.g., tracheal intubation, non-invasive ventilation, tracheostomy, cardiopulmonary resuscitation, manual ventilation before intubation, bronchoscopy) healthcare workers should also use an appropriately fitted P2/N95 respirator.
During the current shortage of PPE, all efforts should be made to minimize the chance of exposure using other methods. These measures include administrative, environmental and engineering controls, such as limiting paths of entry to clinics, installing physical barriers and the establishment of triage stations to screen patients outside the facility. Using eye and face protection should be prioritized during procedures that generate splashes and sprays or when prolonged face to face proximity is unavoidable. The CDC & ECDC have included proposed strategies for further optimization of eye protection that can be found on their websites.(3, 4).
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Use and re-use
If eye protection is to be re-used, it is important to ensure appropriate cleaning and disinfection between uses. Eye protection should be discarded if damaged. If it is dirty or difficult to see through it should be replaced. Health care workers should leave the patient care area before they remove their eye protection.
Eye Protection Standards
Currently there is no standard explicitly for eye protection against biological hazards, such as COVID-19. Goggles or faceshields are proposed as appropriate protection for the eyes. However, as the primary method of infection is by droplet rather than airborne transmission, closely fitted wraparound safety glasses that comply with the minimum coverage requirements for eye protectors, ANSI Z87.1 (impact rated, marked “Z87+”) (5) or EN166 (Increased robustness, masked “S”) (6), AS/ NZS 1337.1 (medium impact, marked “I” or “F” ) (7); could be used in circumstances when there is no aerosol generation.(3). Note: The specification of an impact grade is because lateral protection is part of the impact requirement not because protection against impact is required in this circumstance.
Given the limited coverage that they offer, especially from the side, prescription spectacles will not provide adequate protection. In this case the best option is to provide a face shield or goggles over the top of the prescription spectacles or goggles fitted with prescription lenses, taking care to ensure that fit and coverage are not compromised by the combination.
What is defined as close contact?
Greater than 15 minutes face-to-face contact in any setting with a confirmed or probable infected person in the period extending from 24 hours before onset of symptoms in that person, or sharing of an enclosed space with a confirmed or probable infected person for a prolonged period (e.g. more than 2 hours) in the period extending from 24 hours before onset of symptoms in that person.
Basic protective measures against coronavirus: Standard precautions, including hand hygiene, should be observed for all patients.
Wash your hands frequently: Regularly and thoroughly clean your hands with an alcohol-based hand rub or wash them with soap and water for at least 20 seconds.
Maintain social distance: Maintain at least 1.5 metres between yourself and anyone. Avoid shaking hands or hugging or kissing individuals even those without symptoms.
Practise respiratory hygiene: Make sure that you and the people around you follow good respiratory hygiene. Cover your mouth and nose with your bent elbow or a tissue when you cough or sneeze. Dispose of the used tissue immediately.
Avoid touching your face, particularly eyes, nose and mouth: Hands touch many surfaces and can pick up viruses. Once contaminated, hands can transfer the virus to your eyes, nose or mouth. From there, the virus can enter your body and make you sick.
Regularly disinfect commonly touched surfaces.
Avoid large gatherings and crowded areas.
Stay home if you feel unwell. If you have a fever, cough and difficulty breathing, call in advance and seek medical care. Follow the directions of your local health authority.(8)
Transmission-based precautions:
Contact and droplet precautions should be observed for routine care of patients in quarantine or under investigation or with suspected or confirmed COVID-19 infection.
Contact and airborne precautions should be observed when performing aerosol generating procedures and providing care to patients with severe respiratory symptoms.
Authors : Annette Hoskin , Stephen J Dain