Regions of the world that showed an early interest in face masks had milder COVID-19 outbreaks, according to a new letter to the editor published in the American Journal of Respiratory and Critical Care Medicine.

Researchers from the Chinese University of Hong Kong shared findings from their analysis of how public interest in face masks might have impacted the severity of COVID-19 and possibly contained the outbreak in 42 countries on six continents.

In their analysis, the authors wrote: "In many Asian countries like China and Japan, the use of face masks in this pandemic is ubiquitous and is considered as a hygiene etiquette, whereas in many Western countries, its use in the public is less common."

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Researchers found a clear correlation between the awareness or general acceptance of wearing a face mask and infection rates. "One classic example is seen in Hong Kong," Sunny Wong, associate professor of the Department of Medicine and Therapeutics at the Chinese University of Hong Kong, said in a statement.

Despite Hong Kong's proximity to mainland China, its infection rate is modest, with only 1,110 cases to date. The use of face masks in the city is extremely widespread, up to 98.8 percent by respondents in a survey. Researchers observed similar patterns in other Asian areas, such as Taiwan, Thailand and Malaysia.

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As of Thursday evening, there are more than 9.5 million cases and at least 484,880 deaths worldwide from COVID-19. The United States accounts for more than 2.4 million cases and at least 122,481 deaths.

Early face mask adoption linked to modest infection rates.

Early face mask adoption linked to modest infection rates. (ATS)

Although the authors acknowledge that face masks are likely important in slowing the rise of COVID-19 infections, it is hard to determine whether it is more effective than hand-washing or social distancing alone.

"Face masks can help slow the spread of COVID-19, and have a relatively low cost compared to the health resources and death toll associated with the pandemic," Wong said.

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"We believe that face mask use, hand washing and social distancing are all important components of the non-pharmaceutical measures against COVID-19," he added.