Tokyo (AFP)

The use of masks in the face of the coronavirus has been spontaneous and massive in certain regions of Asia, while the Western countries, initially reluctant, are beginning to recommend their general use. However, the effectiveness of this strategy is still debated.

Experts agree that there is little, if any, evidence that ordinary surgical masks, commonly used in Asia during the winter flu season and hay fever season in the spring, effectively protect against the Covid-19.

Proponents of masks, however, point out that infected people must wear them to avoid transmitting the virus, and that it has been shown that an infected person can already be contagious before experiencing symptoms.

The relatively low number of Covid-19 cases so far in Japan and Hong Kong, for example, has further strengthened the beliefs of pro-masks.

In these territories, wearing a mask was one of the immediate responses to the health crisis. The Japanese government has also announced Wednesday that each household will soon receive two reusable masks.

"But where I grew up in the United States, some people see wearing a mask as an assault on their person - an obligation imposed, unwanted," he adds.

- "False sense of security" -

For Ben Cowling, another professor at the same university in Hong Kong, the credit goes to the public health measures taken by some governments in Asia.

This includes "identifying the cases and isolating them, quarantining their relatives, and applying a principle of social distancing," he told AFP.

Mr. Fukuda also warns those who believe in an almost "magical" protective force for masks. "Certain territories like Singapore have done very well overall without insisting heavily on masks," he said.

He too attributes the low spread of the pandemic in these territories to measures such as the systematic identification of relatives of an infected person, good coordination of authorities and respect for social distance - sometimes rooted in local culture, such as in Japan.

In addition, the populations of these regions, which in particular still remember the SARS epidemic (2002-2004), "were also concerned from the start and eager to cooperate with the health authorities", observed Mr. Fukuda. "It is the combination of all these factors that is important."

The World Health Organization (WHO) continues to advise against wearing the mask for the general public, drawing attention to the global shortage of these products and the crucial need to distribute them as a priority to medical personnel on the front line.

In addition, some experts point out that a generalized wearing of masks can have perverse effects, even if stocks are abundant.

"Masks can give people a false sense of security," warns Simon Clarke, an associate professor at the University of Reading (UK), a specialist in cell microbiology.

- Better than nothing -

Wearing a mask thus risks inciting some to not respect the recommendations of social distance for example, underlines Mr. Clarke.

"We all know people who don't care about coming to work with their colds and spreading it to everyone - so will the coronavirus."

Despite these risks, Western countries, seeking by all means to curb the pandemic, are beginning to recommend masks for all.

The wearing of mandatory masks has started to spread in Central Europe, France has ordered more than 1.5 billion masks while the United States is now considering recommending that all Americans wear them, once enough stocks will be available.

Professor Cowling in Hong Kong believes, however, that more research is needed before deciding on the usefulness of this or that type of mask against the pandemic.

However "even if wearing a mask could only slightly reduce transmission (of the virus, editor's note), it would still be a good step to take," he concludes.

© 2020 AFP