Face Masks and COVID-19

DIY infection protection is becoming more popular, but is it effective?

With NSW facing a potential second wave of COVID-19, the reality of compulsory face masks could be just around the corner.

IHMRI’s Jane Whitelaw from UOW’s School of Health and Society says face masks can be effective in minimising transmission of Coronavirus but they have to be well designed.

“To be effective you need a minimum of three layers of material. Homemade masks won’t give as much protection. To be as effective as a surgical mask, you need up to 12 layers.”

Ms Whitelaw advises that any mask should be made of at least 3 layers with a high thread count cotton (300-400) on the inside to absorb moisture from your breath, the middle layer should be a hybrid (such as cotton–silk, cotton–chiffon, cotton–flannel) blend which will give some electrostatic filtration properties and an outer layer of polyester nylon. A nose clip and adjustable ear elastics will assist in gaining a tighter fit which can increase the effectiveness of the mask by 5 times.

Ms Whitelaw says COVID-19 aerosols or droplets remain viable for up to 3 hours. During this time, exposure, inhalation, and infection can occur both near and far from a source.

“There is mounting evidence that demonstrates close range aerosol transmission of COVID-19 by inhalation of microscopic particles. These particles are released not just when we cough and sneeze, but during exhalation and speech,” added Ms Whitelaw.

Ms Whitelaw says this has implications for how we manage exposure to COVID-19 in a community and occupational setting. “The route of exposure is not just contact with droplets from infected individuals in close proximity, but also from smaller aerosols that don’t settle quickly. Transmission of COVID-19 has been shown to be a result of particle concentration in the air and the time people are exposed to that concentration, it has not been shown to be caused by short random interactions between individuals.”

Ms Whitelaw says P2 respirators are considered the most protective option for people who work in health and medical services. Surgical masks will reduce the dispersion of virus droplets from an infected person but have limited use as a personal protective device. There is little evidence that they are effective against smaller aerosolised particles.

Is your face mask good enough?

  • If people are going to wear a mask, it should be fitted before they go out in public and left in place for the entire time they are exposed. Touching and adjusting the mask may lead to contamination of the hands and face and increase the risk of infection. Care must be taken when removing the mask to reduce contamination. Dispose of it immediately. If the mask is a reusable type, place it straight into a plastic bag without touching the outside, and wash daily in hot water. Be mindful that repeated washing will reduce the efficiency of the face mask.

Advice on staying safe:

  • Keep your distance from others
  • Get tested if you have symptoms
  • Use a mask as a last resort in enclosed areas (the tighter fitting the better)

AND importantly for those in hotspot areas:

  • Improve the ventilation in all indoor settings (homes, workplaces, restaurants, public transport, gyms) have adequate ventilation (fresh air) by opening windows wherever possible and increasing fresh air intake in air-conditioned areas. Recirculating air should be passed through a high-efficiency filter.

Front line health care workers:

  • Repeat risk assessments taking into consideration the route of airborne transmission
  • Have regular COVID-19 test screening
  • If in a high-risk situation, wear a correctly fitted P2 (N95) surgical respirator. In all cases, respirator fit testing and training must be provided for the make and model of respirator worn and respirators with valves are not recommended.

Read more about Jane Whitelaw:

Jane Whitelaw is a Certified Occupational Hygienist, Certified Industrial Hygienist and Fellow of the Australian Institute of Occupational Hygienists. Ms Whitelaw is an expert in Respiratory Protection with current research grants & recent publications investigating the efficiency of respirators against airborne particles; and is a member of the Australian Standards Committee SF10 publishing AS/NZS 1715 &1716 on Respiratory Protection (Design and Use). As a PhD candidate in UOW’s School of Medicine, Ms Whitelaw is investigating the “Physiological Effects of Respirator use. Further to this, Ms Whitelaw is the Discipline Lead in the National and Internationally Accredited Occupational Hygiene Academic Program.

Media contact

Louise Negline, Communications Coordinator

m: 0417 044 867

e: louisenegline@ihmri.org.au

 

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