A new study suggests that double-masking does not stop people from catching or spreading covid — and it might even raise their risk.
U.S. health chiefs have been advising Americans to double-up if they cannot get their hands on a medical-grade mask since early 2021, claiming it increases protection but now researchers say wearing two masks may actually do the opposite, by creating "a false sense of security "that causes people to take unnecessary risk.
Wearing two cloth masks can also force more air through the gaps between the face, increasing the amount of virus breathed into the air, they found.
The study, which used computer simulation models, looked at cloth masks so the findings do not necessarily apply to surgical masks or N95s used in hospitals.
However, the researchers noted that wearing two tight-fitting masks could cause 'breathing difficulties'.
The Centers for Disease Control and Prevention (CDC) recommends wearing a cloth mask on top of a surgical mask to achieve a 'better fit and extra protection'.
Experts from Florida State University and Johns Hopkins University made computer simulations of 3D heads based on 100 men and 100 women.
The researchers simulated a cough jet from the mouth of the models, which wore a cloth mask over the nose and mouth and elastic hoops wrapped around the ears.
The team calculated the filtration efficiency, which measures how much virus-filled droplets are captured or blocked by the mask.
The findings, published in the journal Physics of Fluids, show wearing two face coverings provide 'negligible, if any, increase in protection'.
Two masks "might not significantly improve" the protection against breathing out virus particles.
However, they said while it could "theoretically" reduce the amount of virus that could pass through the mask, if two good-fitting face coverings are worn, it "could also lead to breathing difficulties".
A second poor-fitting masks decreases the amount of air that can be filtered through the covering — forcing more air through any gaps between the mask and face.
They said people could also have a "false sense of security when choosing to double mask", and therefore be less likely to social distance or take other precautions.
Double masking has become "more and more popular" for many people who cannot access the most effective N95 and KN95 masks, the researchers said, which makes the findings important.
They said one cloth mask would be better than two but the best type of mask is one that fits tightly like an N95 or KN95.
UK health chiefs have previously said there is "insufficient evidence" to recommend double-masking.
Covid is mainly spread through droplets an infected person releases when they breathe, speak, cough or sneeze.
Large particles can land in the nose or mouth of people nearby, while smaller airborne droplets stay suspended in the air can be breathed in.
Evidence shows that, when worn correctly, masks can reduce the spread of these particles — but by how much is still contested.
News (2)
Beijing upgrades control, Shanghai clears counterfeiting, Zhengzhou puts forward a week to clear covid
Under the CCP's extreme zero-covid policy, chaos has occurred frequently in China. On Wednesday, Beijing began tightening controls on public transport, shutting down some routes. People in Shanghai broke out that the authorities began to cheat in order to "clear" the goal. Zhengzhou has made a promise to achieve social zero within a week. Public opinion believes that this is incomprehensible. Does the virus particularly favor the Zhengzhou Municipal Government, or does the authorities have more extreme means to achieve the goal? In Beijing, the third round of large-scale mandatory nucleic acid testing began on 3 May, and on 4 May, the control of public transportation was tightened, and 6 subway lines were closed, involving more than 60 stations. 158 bus lines were suspended, mainly in Chaoyang District, where the number of cases was relatively high. Ms. Wang, a resident of Beijing, revealed: "One more thing in life is to do nucleic acid on time. Otherwise, you won't be able to go out or get into the car, which is very scary."
In addition, the number of medium and high-risk areas has been increasing (13 high-risk areas, 34 medium-risk areas, and the rest are low-risk areas), and the control of school districts and communities has become more stringent.
Mr. Ye, a resident of Beijing, said, "Many places are closed. My yard is doing nucleic acid every day. There are so many people. It's similar to Shanghai. There's no way. Who told us that we have a one-party system? There are no human rights."
In Shanghai, more than a month after more than 26 million residents were severely locked down, some areas allowed residents to go out for a short time this week but the latest data shows that there are still confirmed cases outside the control area and isolation area, which will be resolved in the short term. They are hopeless.
Mr. Jiang, a resident of Shanghai, said, "What is international leadership is just an appearance. This time the epidemic has all been exposed. The so-called unblocking is a lie. The barbed wire has not been dismantled. 3 hours, is this called unblocking?" ((Shanghai Weijie block tricycle old-fashioned tools walk all over the street))
In order to achieve the goal of "zeroing" as soon as possible, the Shanghai authorities even collectively fabricated fakes, allowing those who tested positive to not do nucleic acid tests, or adopting delaying tactics to continuously review and wait for patients to turn negative.
Sun Hongqin, a resident of Jing'an District, Shanghai, said, "From the evening of the 30th to the morning of 1 May, I took a total of five times (self-test), and the five times were the same (result), two bars (positive). In the afternoon of 1 May, he came to test me. It has been three days today, and my test report has not come out. This is definitely not normal. So, I said, this is a political virus and a profit virus. It turns out that they work for the sake of profit, against conscience, the negative is regarded as the positive and people are pulled into the square cabin to deliberately spread the virus. Now, for the sake of political achievements and political needs, now the positive ones are repeatedly asked to be reviewed and re-examined. "
In Zhengzhou, the resident population is more than 12 million. After people gathered to grab vegetables on 3 May 2022, three mandatory nucleic acid tests were launched on Wednesday for three consecutive days. Except for the closed control area, all the main urban areas are designated as control areas, and the people "stay at home and manage it in a closed manner."
Ms. Zheng, a resident of Zhengzhou, said: "The government didn't stand up and say that the supplies are sufficient. We were all scared when we heard it, so since yesterday afternoon, almost all family members have been like crazy, all rushed to the supermarket and vegetable market to grab food, go to stock up."
Zhengzhou city government personnel said, "After everyone has finished the nucleic acid, come to me and find me to get the pass, one pass for each family."
The authorities claimed to achieve "social zero" within a week of the lockdown.
Democracy activist Kang Penghu said, "Communist officials do not need to be responsible to the people, and the people have nothing to do with him. The key is that they are responsible to their superiors. Where is the epidemic now, where is the official position? They're about to be taken down. So when there is trouble, they panic very much, and they are very strict and perverted in this kind of prevention and control.”
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