On January 25, the day after Wuhan was closed, I passed by the newly-built Beijing Daxing Airport and attended an international scientific conference and saw a surprising sight. Nearly 100% of people wear masks (including myself). Even in China, where the epidemic is severe, this is very unusual. After arriving in Europe, I couldn't find anyone wearing a mask.
Three months later, even if more than 30 countries/regions, including Germany, require the public to wear masks outdoors, the British government has always insisted that there are not enough arguments to support such a move. The government will quickly decide whether it is necessary to wear a mask under the advice of the Emergency Scientific Advisory Group.
The report shows that the recommendations reached are compromised: they allow the public to choose to wear a scarf or cover their face instead of wearing a medical mask. Then why are there such differences on this issue?
Most of us may ask: How can masks, especially masks made of cloth, protect us from the new coronavirus? However, the concept of "protection" ignores the main reason why more and more people around the world wear masks to cover their faces.
Since February, data has shown that, unlike SARS (atypical pneumonia patients will be the most infectious a few days after the onset of severe symptoms), people infected with the new coronavirus will be infected before or when the symptoms appear (usually Very mild forms) have spread most viruses, and these viruses are infectious.
This raises two questions: First, the work to contain the new coronavirus is orders of magnitude more difficult than the containment of SARS. Second, what is controversial is that the official recommendation of the World Health Organization and the British government is: only the symptomatic public and their relatives wear masks.
In the field of infectious diseases, the practice of preventing patients from infecting others is called "controlling the source of infection." For respiratory infections, controlling the source of infection should include wearing a mask when not in isolation. The government advocates source control, so people with symptoms are advised to wear masks.
But what if only half of the people with symptoms are? After systematic testing, whether it is passengers on the Diamond Princess or women who are about to give birth in New York, the number of people who are positive for the virus but asymptomatic is about half of the total number of confirmed cases. (The range is 20-90%, but most people agree that the actual data is 40-60%)
So, can people who are completely asymptomatic can spread the new coronavirus? We know that even normal speech can spread droplets, and the use of masks can greatly reduce droplets. For a symptomatic person, whether he is infected with the new crown virus or the flu, normal breathing can also cause the spread of the virus, which can be stopped by wearing a mask. Although we are not sure how contagious asymptomatic patients are, there is evidence that approximately 40% of transmission cases come from asymptomatic infections.
So, what objections does the public have to wearing masks? There have been many debates on this issue, and the evidence for wearing masks is fragile and ambiguous. For doctors, the "gold standard" of evidence is a randomized controlled experiment (some people take drugs or intervene, some don't, depending on whether it is beneficial or risky).
There have been some experiments with masks before, involving the prevention of influenza, and the results were disappointing (although most people who planned to wear masks did not actually wear them). It turns out that we are not afraid of catching the flu.
However, if people seek the same level of evidence for other measures strongly advocated by the government (such as hand washing), the research is also disappointing. For other suggestions (such as keeping a safe distance of two meters, or isolation), there is no experiment at all.
Therefore, wearing masks seems to be different from other measures and receive different standards of treatment. Although there is no experimental data, "natural experiments" do show that there is at least a correlation between wearing a mask and reducing the spread of the new coronavirus. The city of Jena in Germany started to wear masks on March 31. There were no new infection records within eight days, while the surrounding cities continued to show an upward trend.
Other objections include: wearing a mask will increase other dangerous behaviors, such as a relaxed attitude after wearing a mask (similar to mandatory legislation for vehicle owners to wear seat belts, and people wearing seat belts will increase their dangerous driving behaviors), or being polluted The mask will increase infection. But in Hong Kong, the holding rate of masks has reached an astonishing 98%. There is no report on the harm caused by this practice. In fact, only four people have died of the new crown virus in Hong Kong since the outbreak.
Perhaps the last objection is that masks are a scarce resource, and the public wearing masks will compete with medical institutions for resources. In this sense, the government may be stalling because of the lack of masks. This is a political and economic issue, not a scientific issue.
This can also explain the recent focus on cloth masks or other face masks: by promoting these things, there is no need to fight against the national medical service system. Moreover, the government recently cooperated with Rolls-Royce to produce ventilators. This partnership between the government and other industries can also ensure that high-quality masks are provided for everyone in the country.
Because of the government's hesitation, we and our European neighbors are no longer the same. The British public may eventually become the mice of the "control experiment with masks." But do we really want this?