Children learn how to wear face masks at a kindergarten in Changsha, central China's Hunan Province, May 11, 2020. Changsha gradually reopened kindergartens from Monday. (Xinhua/Chen Zeguo)

The WHO's admission that the virus which causes COVID-19 can spread through airborne transmission proves that China's mandatory mask policy has saved millions of lives, and should rings a special alarm to countries that relaxed restrictions too fast and too soon, warned a Chinese virologist. 

Experts at the WHO Tuesday acknowledged there is growing evidence the coronavirus can spread through air and said they are preparing a brief on the subject.

The information was like a bomb in the water for some Western countries that have been long rejecting mask wearing, which virologist warned is the only way to prevent airborne transmission. But Chinese people are less surprised, as they were cautious about air transmission as early as in January and has been carefully protecting themselves ever since.

On Saturday, The New York Times reported that 239 scientists will warn the WHO that the virus can linger in the air and infect those nearby. The researchers plan to publish their evidence in a journal soon.

"But the air is now clear of the virus in many Northern Hemisphere countries, at least in China now because of the high temperature," Yang Zhanqiu, deputy director of the pathogen biology department at Wuhan University, told the Global Times, noting that virus can remain active in the air for 24 hours in spring and autumn, but for only a few hours in summer. 

Yang said that Beijing's Xinfadi market outbreak provides proof, as the contagion concentrated only in certain sub-districts in the city, but other districts were less or not affected at all. 

The virologist said the WHO's theory may ring a special alarm for some Western countries, especially the US, which are still being ravaged by the virus but have seen many people reject the idea of mask-wearing.

US President Donald Trump and Brazilian President Jair Bolsonaro have always been stubborn opponents of masks. Both populist leaders have repeatedly refused to wear masks at public gatherings. Bolsonaro even took off his mask at a press conference Monday after testing positive for the virus.  

Yang said the strain of the virus in those countries may be more contagious than that in China, which makes it even harder for them to curb the transmission completely. To verify his theory, Yang cited German and UK scientists study suggesting that the virus has three central variants, which were found in significant proportions in East Asia, Europeans and Americans respectively. 

"In China, we took timely measures to curb the flow of people and imposed quarantines. So the genotype of the virus which is endemic to China is simple. However, the US and some parts of the Europe may face a hybrid coronavirus, which may be more contagious and makes their battle more arduous," said Yang. 


Newspaper headline: Mask-wearing policy essential as WHO admits virus is airborne