MEDICAL MASKS ARE NOT INFERIOR TO N95 RESPIRATOR MASKS in protecting healthcare workers against COVID-19. That sounds like good news. Today we look at surgical versus N95 masks.
The study results have sparked international criticism. The findings are inconsistent with those of many other studies. Today, we look at the study, partially funded by the World Health Organization (WHO) and recently published online in the Annals of Internal Medicine.
COVID19 — Surgical versus N95 Masks
Researchers conducted a clinical trial that randomized individuals to surgical versus N95 masks to assess healthcare worker COVID-19 infection risk. The World Health Organization (WHO)provided some funding.
The study occurred in 29 healthcare facilities in Canada, Israel, Pakistan, and Egypt from May 2020 to March 2022. It included 1009 health care workers who provided direct care to patients with suspected or confirmed COVID-19.
Researchers assigned the study participants to wear either medical masks or fit-tested N95 respirators for ten weeks. Researchers confirmed COVID-19 on reverse transcriptase polymerase chain reaction (RT-PCR) test. Here are the research findings:
“Among healthcare workers who provided routine care to patients with COVID-19, the overall estimates rule out a doubling in COVID-19 risk for medical masks compared with N95 respirators. The subgroup results varied by country, and the overall estimates may not apply to individual countries because of treatment effect heterogeneity.”
COVID19 — Surgical versus N95 Masks — My take
I work in a medical setting, regularly interacting with patients with cancer. What kind of mask should I wear? What about the flu and other respiratory illnesses? Is this study the one on which I should hang my hat?
First, the outcomes are inconsistent with those of many other studies. Second, the study is remarkably underpowered; the researchers have ruled out a doubling of risk associated with the use of medical makes (instead of N95 ones).
University of Minnesota (USA) scientists did a detailed examination. CIDRAP reminds us that the study looked at healthcare workers in four countries during differing pandemic periods. Please note that CIDRAP gets funding from 3M, a maker of N95 masks.
Absolute risk difference
So how much more risk do I have if I wear the more comfortable surgical mask instead of, the more unwieldy N95 one? Dr. Mark Loeb, the study’s lead author, defends the findings:
“The confidence intervals around this — the possible results if researchers repeated the experiment many times — range from −2.5 to 4.9 percent. COVID-19 risk for those using medical masks could have ranged from a 2.5 percent risk decrease to a 4.9 percent risk increase. Policymakers and individuals can decide for themselves about this.”
Speaking with Medscape, University of Toronto (Canada) epidemiologist Dr. David Fishman is harsh in his criticism:
“These researchers have been fighting against treating COVID as airborne for three years. Thus, you see these individuals brandishing this flawed trial to justify continuing the infection control approaches that have proven so disastrous throughout the pandemic.”
The takeaway message may be simple: An N95 mask worn intermittently is not much more effective than a surgical mask. Other studies have shown that while surgical masks are designed to block large spray droplets, they allow aerosols (measuring 0.5 to 3 µm and shown to contain infectious COVID-19 virus) to flow through.
These observations mean I will don a surgical mask in a moderate-risk setting like the airport. For high-risk settings, I will wear the less-than-comfortable K95 mask. Each of us needs to decide which approach we are comfortable with, but I work with immunocompromised patients and will continue to lower my risk of flu, COVID-19, and other infections.
The United States currently has its highest number of flu hospitalizations in a decade. Things are not going to get much better soon. As the busy holiday season approaches (with a relatively low number of folks vaccinated against the flu), millions are at risk of severe illness.
While most individuals who get the flu will recover in a few days, some will get life-threatening complications. There have been more than 7,300 deaths from the flu (including 21 children) since October, according to the US Centers for Disease Control and Prevention. Flu infection has led to hospitalization for approximately 120,000 people in the last two months.
Please be careful. That means adequate sleep, physical activity, proper hand hygiene, flu and COVID vaccination, and clean surfaces. And social distancing and masking, where appropriate. Yes, I am tired of it all.
Thank you for joining me in this look at surgical and N95 masks and COVID-19 transmission.
The information I provided in this blog is for educational purposes only and does not substitute for professional medical advice. Please consult a medical professional or healthcare provider if you seek medical advice, diagnoses, or treatment. I am not liable for risks or issues associated with using or acting upon the information in this blog.
