What does the evidence say?
The Background
Public Health England (PHE) updated the Infection Prevention and Control (IPC) guidelines for COVID-19 based on the emerging understanding of the disease transmission. These update guidelines focus on the halt of this novel disease, from hand hygiene to linen management. (The guidelines are available here)
As mentioned before most advice is based on models and projections based on the reasonable assumption that the transmission characteristics of COVID-19 are very similar to those of the 2003 SARS-CoV outbreak. The transmission of COVID-19 as per that of SARS-CoV is therefore thought to be mainly through respiratory droplets generated by coughing and sneezing, and through contact with contaminated surfaces.
Transmission of COVID-19
Droplets expelled during a coughing and sneezing have been shown to be greater than 5μm. These droplets are relatively heavy therefore on travel short distance in the air ~ 1 metre. These can be inhaled or land on environmental surfaces.
Droplet and contact transmission is thought to be the predominantly mode of transmission, therefore evidence suggests that use of either an FFP3 respirator OR a surgical face mask offered a similar level of protection, both associated with up to an 80% reduction in the risk of infection.
Droplet precautions include surgical face mask, plastic disposable apron, gloves and where there may be splashes generated and risk of splash to the face, a visor or goggles. All have there their place and are only effective if worn and removed correctly (“donned” and “doffed”)
Aerosols
Whilst most droplets are larger and cause more risk of transmission. In the healthcare setting, when we undertake certain tasks such as intubation, extubation, tracheotomy, manual ventilation, open suctioning, bronchoscopy, non-invasive ventilation, high flow oxygen. These larger droplets can become aerosols. These aerosols are dangerous due to their potential ability to penetrate the respiratory system to the alveolar level.
Airborne precautions include the use of a FFP3 respirator, disposable gloves, fluid resistant gown, visor or goggles.
GB pharmacy conclusion
It is clear the virus is spread via droplets from inhalation or environment contact transmission.
The use of personal protective equipment is vital in healthcare due to the aerosolization tasks undertaken and unavoidable close proximity to patients, staff and colleagues. After each interaction with a patient the PPE is removed and replaced before interacting with another.
Correlating this to the public domain, I am seeing more and more people wearing masks, this is understandable as we have seen they do have their place plus other countries are making them mandatory.
Yet the issues arise, firstly when these uncomfortable accessories are ill fitting, allowing the air to flow through the sides of the mask instead of through it. Secondly due to their comfortableness, people are constantly adjusting and fiddling with them, hence touching their face!
Bringing us nicely onto the gloves, as mentioned above in healthcare we discard each pair after each interaction. Yet in public, people wear one pair all day. You are literally just spreading the virus around everywhere you touch and go, especially when you adjust that mask of yours!
So if you are wearing a mask, ensure you wash your hand before putting it on. Once on ensure it is fitted correctly to your face, sitting snug to your skin and is comfortable. Avoid touching it or adjusting it without washing your hand first. With gloves use only doing a ‘dirty’ task then discard. Using gloves does not supersede washing your hands.
In short wash hands thoroughly and regularly and keep your 2 metre social distance to avoid the droplets
Want to create your own view? here are my references:
1. Health Protection Scotland. Rapid Review: Infection Prevention and Control Guidelines for the Management of COVID-19. Health Protection Scotland, 2020.
2. Offeddu V, Yung, CF, Low MSF, et al. Effectiveness of Masks and Respirators Against Respiratory Infections in Healthcare Workers: A systematic review and meta-analysis. Clinical Infectious Diseases 2017;65:1934-1942
3. Loeb, M., McGeer, A., Henry, B., Ofner et al. SARS among critical care nurses, Toronto. Emerging Infectious Diseases. 2004;10 (2): 251-255
4. Panagea S, Winstanley C, Walshaw M, Ledson M, Hart C. Environmental contamination with an epidemic strain of Pseudomonas aeruginosa in a Liverpool cystic fibrosis centre, and study of its survival on dry surfaces. Journal of Hospital Infection 2005;59:102-7.
5. Jones A, Govan J, Docherty C, Dodd M, Isalska B, Stanbridge T. Identification of airborne dissemination of epidemic multiresistant strains of Pseudomonas aeruginosa at a CF centre during a cross infection outbreak. Thorax 2003;58:525-7.
6. Jones RM, Brosseau LM. Aerosol transmission of infectious disease. Journal of Occupational and Environmental Medicine 2015 May 1;57(5):01.
7. Coia JE, Ritchie L, Adisesh A, Makison Booth C, Bradley C, Bunyan D, et al. Guidance on the use of respiratory and facial protection equipment. J HOSP INFECT 2013 Nov;85(3):170-82.
8. Fernstrom A, Goldblatt M. Aerobiology and Its role in the transmission of infectious diseases. Journal of Pathogens2013(no pagination):493960.
9. Public Health England. COVID-19 Infection Prevention and Control in healthcare settings. 2020 Public Health England.
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