A research project led by professor Benjamin Cowling at the World Health Organization Collaborating Centre for infectious disease epidemiology in Hong Kong has produced findings that demonstrate surgical masks can reduce the transmission of influenza and seasonal coronaviruses. The study, released on August 20, 2021, examined how masks affect the release of viruses from infected individuals. Researchers discovered that when people suffering from flu wore surgical masks, the number of detectable flu viruses in droplets from breathing and coughing dropped significantly.
Similarly, the use of surgical masks by infected individuals reduced the amount of seasonal coronaviruses found in the air as suspended microdroplets, known as aerosols. The study did not examine SARS-CoV-2, the virus responsible for COVID-19.
As of August 21, 2020, that virus had infected 22,863,816 people and caused 797,133 deaths worldwide. Professor Cowling indicated that the findings could be applied to simpler face coverings.
In a telephone interview, he stated, “My expert view is that cloth or cotton masks would have an effect, but maybe slightly less of an effect than a surgical mask properly worn.” He added, “And in terms of COVID-19, we’re looking at every possible measure that could help.” Rupert Beale, a specialist in infection biology at London’s Francis Crick Institute who was not involved in the research, described the work as offering “strong and compelling evidence” for mask-wearing as a way to reduce transmission of certain viruses. However, he cautioned that masks are not a complete solution.
“Mask wearing does not completely prevent transmission and cannot be relied on as a sole measure,” Beale said. He noted that masks, “combined with other social distancing measures, should form part of the ‘exit strategy’ from lockdown.” Until this study, there has been limited robust scientific evidence regarding the effectiveness of face masks in slowing the spread of respiratory diseases. The new research provides significant insights into how masks can reduce transmission.
The findings are particularly relevant given that SARS-CoV-2 can be transmitted by people showing no symptoms, which has contributed to its rapid spread. Professor Cowling noted that “further research is needed to determine whether masks can specifically prevent the transmission of SARS-CoV-2.” The study’s results have implications for public health policy, suggesting that mask-wearing should be combined with other social distancing measures as part of a comprehensive approach to reducing transmission.
The research provides a foundation for additional studies into mask effectiveness, particularly regarding COVID-19.
