A few hours ago, Nature’s sub-magazine, Nature Medicine, published a brief newsletter online. As soon as it went online, the post was immediately posted around the world and retweeted tens of thousands of times on Twitter alone. According to statistics, its popular influence has exceeded 99% of other articles of the same period.
As of the time of writing, this article is still explosive on social media (photo source: Screenshot of Nature’s official website)
Interestingly, this hot global newsletter is not a disruptive discovery. Instead, it concludes that it is common sense for many of us to wear a mask that helps reduce the spread of some respiratory viruses. Yet such a common sense has caused a global uproar.
In the paper, the authors note that surgical masks were originally created to protect surgical patients from contaminating their wounds. Subsequently, medical staff began to wear surgical masks to avoid infection by patients exposed to at work. But does surgical masks really help filter out respiratory viruses and reduce their spread? In fact, there is a great lack of information. As to whether surgical masks have an effect on coronaviruses, there has been no definitive answer.
The article has caused a stir on social media overseas (Picture: Twitter-related search screenshot)
That’s what this newsletter is all about. To clarify the role of wearing masks in reducing the spread of the virus, the WHO Collaborating Centre for Infectious Disease Epidemiology and Control, in collaboration with the University of Hong Kong, led a study and recruited 246 volunteers (123 of whom were infected with at least one respiratory virus, or 50 per cent). The volunteers were randomly divided into two groups, one wearing a mask and one group wearing a mask, about half of them.
The researchers then analyzed whether masks had a significant inhibitory effect on reducing the spread of respiratory viruses. They chose three respiratory viruses: seasonal coronaviruses, influenza viruses, and rhinoviruses. It is important to note that the seasonal coronavirus selected here is not the new coronavirus of this outbreak. However, considering that the particle size of the two is close and close, it can be used as a reference to some extent.
The study found that in the “no mask group”, whether the volunteers exhaled droplet samples (size greater than 5 microns), or aerosol samples (size less than 5 microns), can detect coronaviruses, the proportion of 30% and 40%, respectively. For volunteers wearing masks, the scientists did not detect any coronavirus esmalvirus in their exhalation samples! Statistically, masks significantly reduce the spread of aerosols of coronaviruses. In the spread of droplets, there is also a clear trend of reduction.
This study assessed the effect of surgical masks in reducing the spread of multiple respiratory virus droplets and aerosols (Photo: Resources 1)
On other respiratory viruses, masks perform differently: they significantly reduce the spread of flu virus droplets, but do not seem to help reduce the spread of the flu virus aerosols. There was no significant difference in the absence of a mask.
In the discussion section of the paper, the authors note that the study highlights the effect of surgical masks in reducing the spread of droplets and aerosols of seasonal coronaviruses. This may have important implications for controlling diseases caused by the new coronavirus, which may help slow the spread of the virus by wearing such masks in people with new coronavirus infections. The authors also point to some limitations in the study, such as the testing methods used to assess the virus’s content, not the virus’s infection.
In conclusion, in this study, scientists found that surgical masks significantly reduced the amount of coronavirus RNA detected in aerosols (and the amount of influenza virus RNA detected in droplets). These results suggest that surgical masks can prevent the spread of human coronaviruses and influenza viruses in a symptomated individual.