— Augmenting protection during a global pandemic
While it may not be evidence-based in the rigid scientific sense, wearing a basic face mask in the community setting to augment our protection against SARS-CoV-2, the virus that causes COVID-19, is biologically plausible, and potentially impactful.
The basic or standard surgical mask, also referred to as a fluid-resistant surgical mask, is designed to serve as a “barrier to splashes and droplets impacting on the wearer’s nose, mouth and respiratory tract.” Recommendations from authorities discouraging the use of a face mask by the general public may have been optimal earlier, when there was generally no or low community spread of the virus in the U.S., and given the critical shortage of face masks for use in the healthcare setting.
But those recommendations may be changing now that there is exponential community spread of the virus in the U.S., the current epicenter of the pandemic, particularly New York City, not to mention, we now know that the virus is highly contagious and virulent with potential asymptomatic and pre-symptomatic spread.
Moreover, with the increasing threat posed by this virus, the public is more likely to comply with wearing a face mask than the other non-pharmaceutical interventions, particularly social distancing and staying at home. Wearing a face mask appropriately could prove a more cost-effective risk-reduction strategy, and in view of the critical shortage, a homemade mask made from common household materials could be an acceptable substitute.
In one study, homemade cotton face masks, while not as effective as the disposable surgical mask, “significantly reduced the number of microorganisms expelled by volunteers” with influenza. The study concluded that “a homemade mask should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection.”
George Gao, director-general of the Chinese Center for Disease Control and Prevention recently noted that: “The big mistake in the U.S. and Europe, in my opinion, is that people aren’t wearing masks.” Notably, China was the initial epicenter of this pandemic, but the spread is now under control and rapidly abating. According to the World Health Organization (WHO), SARS-CoV-2 is transmitted directly between people through respiratory droplets, and indirectly from contaminated surfaces, and objects (also known as fomites). Specifically, droplet transmission occurs when a person is within about three feet from someone who has respiratory symptoms, such as coughing and sneezing. Hence the social distancing guideline of six feet of separation from others is considered sound as a protective measure, but compliance remains a major challenge.
In addition, a recent controlled laboratory study reported that aerosol transmission of SARS-CoV-2 is plausible “since the virus can remain viable and infectious in aerosols for hours,” suggesting that “people may acquire the virus through the air”. Aerosols result from the evaporation of droplets, and are therefore much smaller and contain the virus. These aerosols “may remain in the air for long periods of time” and be transmitted to others over distances greater than one meter or approximately three feet. Indeed, “coughing and sneezing can generate aerosol particles as well as droplets.”
While COVID-19 is not currently classified as an airborne disease, airborne transmission of the virus may be possible when certain medical procedures are performed. Amidst this evolving historic public health crisis, let’s not forget the scientific value of good logic and reasonable inference, as we seek to reduce the risk of infection to the general public.
Rossi A. Hassad, PhD, MPH, is an epidemiologist and professor at Mercy College, in Dobbs Ferry, New York. He is a member of the American College of Epidemiology and a fellow and chartered statistician of Britain’s Royal Statistical Society.
Source: Medpage Today