Can we stop the development of coronavirus if everyone wears masks?

Keep a safe distance of 1 to 2 meters, wash your hands frequently with soap and water or disinfectant gel and stay home- these are the instructions the citizens of the world have received from their respective governments and the World Health Organisation (WHO). 

When the WHO Director-General Tedros Adhanom Ghebreyesus declared the new coronavirus a worldwide pandemic on March 11, hysteria gripped many people who hit pharmacies with the aim of stocking up on masks and hand sanitizers. The panic buying didn’t end there, other ‘hot commodities’ including surgical alcohol (for wounds), FFP3 and FFP2 masks, toilet paper and various kinds of grains quickly sold out in many countries, despite endless reassurance that there would not be a shortage of those items. 

Due to this panic buying, things became even more difficult as medical personnel no longer had the protective equipment to deal with the ever-increasing number of infected people. Experts recommended that only those who showed symptoms of COVID-19 or were caring for people with the disease should wear a mask. The rest of the population should continue with the aforementioned protective measures.

March 14 arrived and the declaration of the state of alarm led to even more hysteria. When you go out on the street to do your essential shopping, a good number of the people you see on the streets or in stores will be wearing a mask. You can observe how many people touch the front part of the mask (where the virus would be) with their hands and sometimes you can even see people take off their mask by touching the front of the mask or even worse lowering it below the nose... This erroneous behaviour when handling a mask is the result of the lack of knowledge of the general population about how to use this product. In addition, the use of a mask can generate a much-feared false sense of security, that is, that by wearing it you think you are totally protected and you neglect such important protective measures as frequent hand washing and maintaining a safe distance between people.

Are masks really unnecessary for the asymptomatic population? An article published in the magazine Science on 28 March includes several statements by international experts who claim the opposite. "It's really a perfectly good public health intervention that's not used," argues KK Cheng, a public health expert at the University of Birmingham. "It's not to protect yourself. It's to protect people from the droplets coming out of your respiratory tract.

On the other hand, those in favour of people wearing masks say their impact on the spread of the disease is likely to be modest. Many are also afraid to promote the purchase of masks in the midst of a major shortage in hospitals. Mark Loeb, a microbiologist and infectious disease physician at McMaster University, says, "I don't think it's good public health policy for people to go out and buy N95 medical masks and respirators and wear them on the street.

However, as the pandemic spreads, some public health experts believe that government messages discouraging their use should change.

The director of the Chinese Center for Disease Control and Prevention believes that not wearing a mask is a mistake. In fact, health authorities in some parts of Asia have encouraged all citizens to wear masks in public to prevent the spread of the virus, whether or not they have symptoms. The Czech Republic made their use in public spaces mandatory, launching a campaign to make them at home.

The CDC (U.S. Centers for Disease Control and Prevention) recognizes that making homemade masks may be the last resort for health care workers who lack other protection. However, rigorous studies comparing fabric masks with surgical masks or investigating the ideal material for homemade masks are lacking.

Although there is some evidence that SARS-CoV-2 can persist in aerosols, fine particles that remain suspended in the air are likely to be rare, says Arnold Monto, an epidemiologist at the University of Michigan, Ann Arbor. It is spread mainly by larger droplets "and we know that standard surgical masks will have a modest effect on that type of transmission," he says. "When [the masks] are combined with other approaches, then they can make a difference.

Despite messages from some health care workers to the contrary, it's likely that a mask can help protect a healthy carrier from infection, says Benjamin Cowling, an epidemiologist at the University of Hong Kong. Both surgical masks and the more protective N95 respirators have been shown to prevent various respiratory infections in health care workers; there has been some debate about which one is appropriate for different types of care for patients with respiratory infections. "It doesn't make sense to imagine that...surgical masks are really important for health care workers but then not useful at all for the general public," says Cowling. Masks may work better in preventing infections in hospitals than in the public, she says, partly because health workers are trained in how to wear them and because they take other important safety measures such as thorough hand washing. "I think the average person if taught how to wear a mask correctly, would have some protection against infection in the community.

As we already know, there are people who are infected and do not show symptoms, so they feel fine and continue to go out to shop, to work( if they do not have the option of home-office), or to take the dog out, and they can transmit the coronavirus without being aware. Cowling and other experts point out that the benefit of wearing masks correctly (putting them on and taking them off according to rules, washing your hands frequently, not touching the front, etc) would protect those who are not infected. The goal, therefore, of covering your nose and mouth would not be to protect you from the coronavirus but not to infect others.

Data from contact tracing efforts - in which researchers monitor the health of people who have recently interacted with someone who has been confirmed infected - suggest that nearly half of SARS-CoV-2 transmissions occur before the infected person shows symptoms. And some people seem to catch and eliminate the virus without ever feeling sick. "If I knew who was asymptomatic and pre-symptomatic [for COVID-19], I would ... classify masks for those individuals," says Monto. Unfortunately, he adds, "We don't know who these are.

Cheng hopes that masks will become more important in the United States and Europe once the peak of COVID-19 cases passes and social distancing restrictions are eased. "Imagine you're riding the New York City subway on a busy morning. If everyone wore a mask, I'm sure it would reduce transmission," he tells Science, adding, "Don't ask me to show you a clinical trial that it works.