Should you really be wearing a mask in public? A medical researcher weighs


With the coronavirus pandemic spreading rapidly, U.S. health officials have changed their minds about face masks and are now recommending that people wear cloth masks in public places where social distancing can be difficult, such as in grocery stores .

But can these masks be effective?

On April 3, President Donald Trump, announcing the change to the guidelines for the Centers for Disease Control and Prevention, stressed that the recommendation was voluntary and said he would likely not follow it.

Governors and mayors, however, have begun to encourage precautions to reduce the spread of the virus by people who may not know they are infected.

Some cities have gone as far as setting fines for failing to wear a mask. In Laredo, Texas, anyone over the age of five who enters a store or takes public transit without covering their mouth and nose with a mask or bandana could now be fined up to $ 1,000.

These new measures are intended to “flatten the curve” or slow the spread of the coronavirus responsible for COVID-19.

They are also a change from the advice that Americans have heard since the start of the coronavirus pandemic.

The World Health Organization and the CDC have repeatedly said that most people do not need to wear masks unless they are sick and coughing.

In February, the American surgeon general even urged the public to stop buying medical masks, warning that it would not contribute to the spread of the coronavirus.

Part of the reason was to reserve N95 respirators and masks for healthcare workers like me who are on the front line and exposed to people with COVID-19.

Today, there is much more data and evidence on how COVID-19 is spread, and the prevalence of the disease itself is much more widespread than previously thought.

Sick, but no symptoms

As early as early February, the World Health Organization said viral transmission from asymptomatic people was likely “rare,” based on information available at the time.

But a growing body of data now suggests that a significant number of infected people who do not have symptoms can still spread the virus to others.

A CDC report released on March 23 on COVID-19 outbreaks on cruise ships provides insight into the danger. He describes how the passenger and crew test on the Diamond Princess found that almost half – 46.5% – of the more than 700 people infected with the new coronavirus had no symptoms at the time of the test.

The CDC said that “a high proportion of asymptomatic infections may partially explain the high attack rate among cruise ship passengers and crews.”

Harvey Fineberg, former president of the National Academy of Medicine and head of a new federal committee on infectious diseases, told CNN on April 2 that he would start wearing a mask in public, especially in grocery stores, for this same reason.

“Although current specific research is limited, the results of available studies are consistent with the aerosolization of the normal respiratory virus,” he said.

It is these “silent carriers” – people infected with the virus but without fever, cough or muscle pain – that proponents of wearing the universal mask indicate as proof that more could be done beyond social distance to slow the spread. of the virus.

More efficient than doing nothing

While research on the effectiveness of wearing the universal mask to reduce the transmission of respiratory droplets is still limited, there is supporting evidence.

Research on SARS, another coronavirus, has revealed that N95 masks are very effective in blocking the transmission of this virus. Even the wrong medical masks interrupt airborne particles and viruses, preventing them from reaching that far when someone sneezes.

Another study determined that, although cotton T-shirt masks were much less effective than surgical masks made to prevent wearers from expelling droplets, they reduced the droplets and were better than no protection at all.

A challenge with the cloth: washing

The surgical masks that doctors and nurses generally wear are designed for single use, while the fabric masks used by the general public would likely be washed, which raises another concern.

A study from Nepal on cloth masks designed to protect carriers of larger particles, such as pollution or pollen, found that washing and drying practices worsened the effectiveness of the mask because they damaged the fabric.

It is clear that urgent research is needed on the best material suitable for universal masks, their storage and maintenance, or the creation of reusable masks suitable for the public.

Low risk intervention

As an obstetrician-gynecologist and researcher, I think that some public protection is better than none. A recent article in the medical journal Lancet respiratory medicine sets out a similar rationale.

The universal use of mouth and nose masks with masks is a low risk intervention that can only help reduce the spread of this terrible disease. If everyone wears a mask, individuals protect each other, which reduces overall community transmission.

It could even remind people not to touch their face after touching potentially contaminated surfaces.

As research shows, masks are not shields. It is always important to help prevent transmission by practicing social distance by staying at least 6 feet (2 meters) from others in public, staying at home as much as possible, and washing your hands frequently and properly.The conversation

Hector Chapa, Clinical Assistant Professor, Director of Interprofessional Education, College of Medicine, Texas A&M University.

This article is republished from The Conversation under a Creative Commons license. Read the original article.


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