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Many N95 masks do not properly fit women or people of Asian descent


Doug Hendrie


19/09/2020 2:46:48 PM

UPDATED: A literature review has found a lack of fit-testing may be placing some healthcare professionals at higher levels of COVID risk.

Inside of N95 mask
Many masks are designed for Caucasian male faces

UPDATED

Women of Asian descent passed initial fit-testing only 60% of the time, according to a recent literature review published in Anaesthesia.
 
The review found women passed initial fit-testing 85% of the time – compared to 95% for men. Healthcare workers with Caucasian backgrounds passed 90% of the time, while those of Asian-background passed 84% of the time overall.
 
The findings pose challenges for Australia’s health workforce, given medical practitioners are now mostly female (53% as of 2014), while 33% gained their first qualification overseas before relocating, according to the Australian Institute of Health and Welfare.   
 
The fit-testing review has taken place against a backdrop of concern over Victoria’s very high rate of healthcare worker coronavirus infection, of which up to 80% were acquired at work.
 
At present, healthcare workers in Victorian hospitals are only required to do fit-checking, inspecting the respirator to see if it is a good seal, rather than fit-testing, which is regarded as a much better – but more time-consuming and expensive – method of proving the respirators protect against aerosols.
 
The Victorian Government on Friday 18 September announced that a fit-testing trial of N95 masks running at Northern Health will also be expanded to all COVID-19 wards in the state. The trial includes nurses, doctors and other healthcare workers.

Healthcare worker advocates long pushed hard for mandatory fit-testing in Victoria.
 
In countries like the UK, healthcare workers with Black, Asian and minority (BAME) backgrounds have been infected with the coronavirus at disproportionately high rates.
 
‘While fit-check remains recommended prior to each use of any respirator to ensure fit on a day-to-day basis, we recommend not to use fit-check as a substitute for fit-testing to identify the size and shape of respirator that fits best,’ the authors of the new review wrote.
 
‘The COVID‐19 pandemic has highlighted deficiencies of some healthcare facilities to protect their [healthcare workers] in line with national and international recommendations.
 
‘Without adequate fit, the degree of airborne protection provided by a respirator is reduced and fit-testing is recommended by international and national bodies to ensure proper fit of filtering facepiece respirators for the individual [healthcare worker].’
 
Study co-author Professor Britta Regli-von Ungern-Sternberg told newsGP that, given how much results varied, the review demonstrates the importance of fit-testing.
 
‘Satisfactory airborne protection will only be provided if the filtering facepiece respirators are properly fitted to the individual’s face, providing a tight facial seal. Airborne protection is decreased in the presence of a leak as unfiltered air will be drawn inside the mask,’ she said.
 
‘The literature shows how varied the results are between masks. If you do a fit-check and a healthcare worker tells you they feel protected, and then you do a fit-test the day afterwards only about 50% of those pass the test. So clearly it is not sufficient to do a fit-check – you have to pass a fit-test and then do a fit-check every time you wear it as well.
 
‘The infections among healthcare workers are pretty frightening. People who do aerosol-generating procedures are much more likely to get infected. It’s now pretty clear COVID is aerosol driven; we don’t have final proof, but it’s pretty clear.’
 
In the first SARS epidemic, healthcare workers exposed to aerosol‐generating procedures were 6.6 times more likely to be infected by SARS‐CoV‐1 than those not exposed, according to a PLoS ONE systematic review.
 
‘If healthcare workers get sick, their colleagues get exposed and have to go into isolation, then you run out of staff – that’s what’s happened to my colleagues in the US, Europe and India,’ Professor Regli-von Ungern-Sternberg said. ‘They struggle to get healthy staff to look after patients.
 
‘In Europe and the US, lots of GPs have been infected. It would be best if governments offered fit testing centres to get the masks you need for your clinic. Mining and construction workers have very regular fit-testing.
 
‘It’s a duty of care to staff and also to the healthcare system. This is a huge problem globally. People either isolate or work when they’re sick, as in some developing countries, and then spread the virus further.’
 
The Australian Society of Anaesthetists recently published the results of internal fit-testing of disposable N95 respirators, as well as reusable elastomeric respirators, showing the disposable N95 respirators passed fit-testing on average only 57% of the time. The more expensive elastomeric respirators passed fit-testing 98% of the time.
 
According to the authors of that report, ‘hospitals should stock multiple types of N95 masks, as it is unlikely for a single type and size to provide adequate protection for the entirety of their frontline staff’.
 
The study comes as a new Annals of Internal Medicine review of studies suggests COVID-19 is spread ‘most often through respiratory droplets or aerosols’ with little evidence suggesting transmission through surfaces exists.
 
Anaesthetist and Associate Professor Alicia Dennis recently wrote that reducing healthcare worker infections is now key to ending Victoria’s lockdown.
 

 
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