With evidence showing face masks are effective in lowering coronavirus transmission, a considerable number of countries are making its use mandatory.  

One of the worst affected regions of the world, Lombardy in Italy, introduced a law making it compulsory for people to wear masks when they step out of their homes. More than 15,877 people have died of COVID-19 in the country as of April 5.

Other European countries are also following suit. Austria enforced mask rule in stores and Jena, a German city, has asked people to cover their faces while shopping and using public transport. Spain is also planning to issue similar directives.

Among Asian countries, Indonesia, Thailand, recently asked people to cover their faces in public areas. But Singapore, on Friday, decided to make a major shift from its policy of discouraging people from using masks.

The government has started encouraging the use of masks in its effort to control the pandemic. Earlier, masks were essential only for people infected with the virus, those showing symptoms, and health care workers. The government has even started delivering reusable masks.

"We will distribute reusable masks to all residents with registered home addresses. The distribution will take place progressively from 5 to April 12," said a statement released by the Singapore's Ministry of Health.

The government's decision to ensure people cover their faces while venturing out of their house comes after realizing that asymptomatic cases are spreading the virus at a high rate.

Countries including China, South Korea and Japan extensively promoted mask use among people to flatten the epidemic curve. But experiences from these countries also show that masks alone cannot control the virus. Social distancing, washing hands and robust surveillance are also crucial.

A recent University of Hong Kong research published in Nature Medicine revealed that surgical masks are useful in controlling the coronavirus spread.

Researchers detected the coronavirus in respiratory droplets and aerosols in 30 to 40 percent of samples collected without face masks, respectively.

"But no virus in respiratory droplets or aerosols were collected from participants wearing face masks, this difference was significant in aerosols and showed a trend toward reduced detection in respiratory droplets," they wrote in the study released on Friday.

"The ability of surgical masks to reduce seasonal coronavirus in respiratory droplets and aerosols implies that such masks can contribute to slowing the spread of SARS-CoV-2 when worn by infected people," said Professor Benjamin Cowling, one of the authors of the study.

Another research published in the journal Nature revealed that, in the first week, people infected with the novel coronavirus spread the infection at a very high rate. And during this period, the infected person shows no symptoms.

The series of evidence prompted global health organizations, including the World Health Organization (WHO) and Centers for Disease Control (CDC), U.S., to revise their guidelines on the use of masks during the pandemic.

CDC recommended voluntary use of cloth masks in the U.S. on April 4.

"We can certainly see circumstances in which the use of masks, both homemade or cloth masks, at community level may help in an overall comprehensive response to this disease," Dr. Michael Ryan, a senior expert with WHO, said at a news conference on Friday.

(People wearing face masks walk at a downtown street in Hong Kong Monday, April 6, 2020. /AP)