Evrim Yazgin
Cosmos science journalist
Two and a half years into the COVID-19 pandemic, case numbers and deaths due to SARS-CoV-2 show no sign of abating and the use of masks and other methods of protection are still as important as ever.
As Melbourne-based data analyst Mike Honey warned on social media earlier in the week, “the next wave of COVID in Australia may already be building. After many weeks of decline, the Reff (case momentum) has begun to increase in recent days, nationally in every state.”
Those of us who have followed the science of the virus and public health measures to stem its spread will have noticed that health and medical experts have had to repeat themselves a lot to get very simple but important health advice across.
For example, for the better part of the last two years, the advice has been that respirators (such as N95 or P2 respirators) are the best face covering for protection against the virus. Personally, wearing an N95 dutifully has likely been the reason I have remained COVID-free.
This must, therefore, be even more important for healthcare workers who are confronted every day with increased risk of infection. A BMJ (formerly British Medical Journal) report from December 2020 found that healthcare workers were seven times more likely to contract severe COVID-19.
So, it should come as no surprise that this week the JAMA (Journal of the American Medical Association) published a study which found healthcare workers were less likely to be infected when wearing high quality N95 respirators.
The study found 35 percent of health workers exposed to COVID-19, who were wearing a mix of surgical masks and respirators were infected.
But in those health care workers who were wearing only respirators, the infection rate dropped to 21 percent.
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The authors write: “The odds of being SARS-CoV-2–positive were reduced by more than 40% in individuals using respirators irrespective of cumulative exposure, even after adjusting for multiple work- and nonwork-related covariables.”
Many public health and medical experts have taken to social media to support the conclusion that respirators offer the best protection. (There is a growth in health professionals taking to public media to get their messages across quickly and with a sense of urgency other communications can’t match – but that’s not the focus of this article.)
Cardiologist Dr Eric Topol said on social media: “The use of high-quality masks (like N95/KN95 respirators) compared with surgical masks, substantially reduced Covid infections among nearly 4,000 health care workers.”
Leading epidemiologist from the University of South Australia, Professor Adrian Esterman, agrees: “Just confirming that N95/P2 masks provide much better protection than surgical masks.”
Even before the JAMA paper was published, eminent Australian immunologist Alan Baxter shared a YouTube video on the physics behind the effectiveness of N95s.
The findings detailed in the JAMA report back up a US CDC (Centre for Disease Control) study published in February this year which looked at face mask vs respirator use in California.
“Face masks or respirators (N95/KN95s) effectively filter virus-sized particles in laboratory settings,” the authors write. Their findings showed that “respirators with higher filtration capacity were associated with the most protection.”
“In addition to being up to date with recommended COVID-19 vaccinations, consistently wearing a comfortable, well-fitting face mask or respirator in indoor public settings protects against acquisition of SARS-CoV-2 infection; a respirator offers the best protection,” the authors add.
So, Victorians should take advantage of Premier Daniel Andrews’s announcement this week that three million N95 and KN95 respirators will be made freely available on public transport, COVID-19 testing sites and community health services.
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