“The point is that countries that flatten the curve use masks in public,” said Chris Kenyon, head of the sexually transmitted diseases unit at Antwerp’s Institute of Tropical Medicine, who investigated whether masks may have played a role in masks. Limit the spread of Covid-19 in certain countries. These are mainly Asian countries. For some reason, European specialists – the Czech Republic (Czech Republic) only recently learned from the success of Asia. ”
To understand why face coverings might work, it’s important to first understand how the virus that causes Covid-19 spreads.
Once someone has been infected, the Sars-CoV-2 virus responsible for the disease hijacks their cells to replicate themselves. As they multiply, these new viral particles burst out of cells and become suspended in the bodily fluids of our lungs, mouth and nose. When an infected person coughs, they can shower tiny virus-filled droplets, called aerosols, into the air.
A single cough can produce up to 3000 drops. There are concerns that the virus can also be spread simply by speaking. Just uttering the word “stay healthy” shows that we can spray thousands of invisible droplets into the air, according to a recent study.
Once out of our mouths, many of the larger droplets quickly settle onto nearby surfaces, while the smaller droplets remain suspended in the air for hours, where they can breathe. At the same time, the behavior of virus-filled droplets in air-conditioned rooms, with less knowledge about the outside environment, is thought to deposit on surfaces more quickly in disturbed air. There have also been reports that the coronavirus can spread through a building’s ventilation system.
When an infected person coughs, they can drop tiny droplets (called aerosols) filled with the virus, a study by a virologist at the National Institute of Allergy and Infectious Diseases and her colleagues showed that Sars-CoV-2 The virus can survive in these aerosol droplets for at least three hours. However, a recent unpublished study found that the Sars-CoV-2 virus remained infectious for more than 16 hours after being suspended in aerosol droplets. The researchers found that the virus was “remarkably resilient in aerosol form” compared to other similar coronaviruses they studied.
They collectively believe that under the right conditions, the virus can remain in the air for hours and still infect people if breathed in. In indoor environments, they appear to be particularly airborne.
An unpublished analysis of 318 Covid-19 outbreaks in China suggests that its most common transmission is in indoor settings, especially in people’s homes, but also in public transport, restaurants, movie theaters and shops. They just found one instance where people appeared to have spread the virus while they were outside.
The genetic material of Sars-CoV-2 has also been detected in the air in toilets and rooms used by people infected with Covid-19. In poorly ventilated spaces, the virus can spread to nearby people through airborne aerosol droplets, a study of a series of cases in a restaurant in Guangzhou, China showed.
“Masks can help reduce transmission in the community, especially when used on public transport and in crowded areas,” said Ben Cowling, head of epidemiology and biostatistics at the University of Hong Kong.
He and his colleagues recently published a study examining the effectiveness of masks in preventing the spread of the virus by infected people. They found that a standard surgical mask was sufficient to greatly reduce escaping from the breath and cough of people infected with different respiratory viruses, including mild coronaviruses, influenza, and rhinoviruses that cause the common cold.
“One of the recommendations for lifting the lockdown is that we will be doing mass testing and contact tracing and quarantining to stay ahead of infections in the community,” the researchers said. “If you are identified as infected, the health department can trace your household. members, your social contacts and professional contacts, but it’s very difficult to keep track of who you are sitting next to a bus or train.
“If we could limit transmission in such locations, that would really help a lot.”
One of the reasons the widespread use of public masks for Covid-19 is so important has to do with the prevalence of asymptomatic carriers who can still spread the virus to others. An estimated 6 to 18 percent of those infected can carry the virus without developing symptoms. Add to that an incubation period of about 5 days, but in some cases as long as 14 days, before symptoms develop, and even those who do appear contagious can spread it to many people before they start falling.
“This makes suppressing transmission within the community particularly difficult,” the researchers said. “However, if everyone wears a mask, it means that infected and asymptomatic people also wear masks. This may help reduce entry into the environment and potentially The number of viruses that cause infection.”
Even wearing a damp homemade mask can reduce the number of droplets each of us emits when we speak, according to a study by researchers.
While masks can help people who already have the virus avoid spreading it to others, do they also protect uninfected people from breathing it in?
Of course, specialized disposable masks (for example, N95 respirators and the European equivalent FFP-2 respirators) have the ability to filter particles from the air. They are designed to passively filter out 95% and 94%, respectively, of airborne particles – as small as 0.3 microns – when the wearer breathes.
However, they have been mixed in keeping the virus out. Some viruses can be as small as 0.01 microns, while researchers report that the coronavirus that causes Covid-19 is 0.07-0.09 microns in size. However, respiratory viruses tend to be suspended in aerosol droplets ranging in size from 0.1-900 microns, so blocking them is often more important.
Some earlier studies suggested that smaller-than-expected viruses could leak through N95 filters, but they have been found to be effective at blocking flu viruses.
And there is some research showing that these respirators are effective in protecting people from Covid-19. An analysis of Chinese health workers showed that people wearing N95 respirators did not contract the virus despite caring for highly contagious patients. That’s one reason why these masks are considered so important to frontline healthcare workers.
If N95 masks are not enough, there are simpler options. A 3M surgical mask (the kind worn by surgeons in the operating room) retains nearly 75% of particles down to a size of 0.02 microns. While far less effective than N95 respirators, surgical masks can still help reduce the number of particles inhaled. However, by cutting a hole in the end of the sock and wearing it over the mask, the mask’s function can be improved to reduce particles to 90 percent.
“Unlike N95 masks, surgical masks are loose in design.”
In countries with mask shortages, some researchers have suggested that prioritizing the use of masks by the elderly may also be effective.
While masks can cause some discomfort and make it harder to spot the facial expressions of the people we’re talking to, these things go a long way in keeping those around us safe and healthy.
