By: Dr. Marc Siegel – wsj.com – May 18, 2020

Should you wear a face mask? Medical authorities have sent confusing messages. Both the U.S. surgeon general and the Centers for Disease Control and Prevention exhorted Americans not to wear masks in January and February, then reversed themselves in April. Mask wearing is now mandatory in many workplaces and public spaces, but how much good does it do? The science is inconclusive, but probably not much.

It’s generally understood that surgical and cloth masks—as distinct from N95 masks, designed to filter fine particles—offer little or no protection to the wearer. The purpose of the mandates is to protect others by ensuring the covering of the face of anyone who is infected. A study published in Nature Medicine in April looked at 246 people with acute upper respiratory illness and found that wearing a surgical mask did decrease spread of genetic material from respiratory viruses, including coronaviruses. The researchers concluded: “We also demonstrated the efficacy of surgical masks to reduce coronavirus detection and viral copies in large respiratory droplets and in aerosols. . . . This has important implications for control of COVID-19, suggesting that surgical face masks could be used by ill people to reduce onward transmission.”

Yet another April study, published in the Annals of Internal Medicine, revealed that the force of sick patients’ coughs propelled droplets through both surgical masks as well as cloth masks.

What about asymptomatic patients? The CDC based its revised mask recommendation on studies that found asymptomatic spread was far more common than had been thought. But there have been no studies on masks’ effectiveness in preventing it. Although the coronavirus is highly contagious, it is much less so than, say, measles, which can linger in the air for two hours after a cough. a sneeze or even speech. By contrast, the Covid-19 virus has not been proved to be aerosolized. Coronaviruses often enter the body through the eyes, and frequent hand and face washing and social distancing is much more effective than masks at preventing that.

Wearing a mask seems harmless, but it could provide a false sense of security, leading people to take fewer precautions. According to the World Health Organization, self-contamination and reuse and or improper disposal of masks can also hinder their effectiveness and turn them into vehicles of spread.

There have even been questions about the effectiveness of N95 masks at protecting medical personnel. They’re considered effective at blocking coronavirus particles only when they’re form fitted and tested to make sure there isn’t any leakage. When I worked on a coronavirus ward, I felt much safer because I also wore a plastic face shield, which blocks viral particles from even reaching the mask.

So wear a mask if you must. But vigilant hand-washing and social distancing will protect you much better.

Dr. Siegel is a clinical professor of medicine and medical director of Doctor Radio at NYU Langone Health and a medical correspondent for Fox News.

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Source: Will a Face Mask Protect You? – WSJ