Letters | Coronavirus crisis: the people of Hong Kong need to know when face masks are a must
- Studies have shown that the use of surgical masks gives some protection against respiratory virus infections even in household and community settings
- The authorities should educate people in areas where there have been community outbreaks on correct surgical mask usage
A common claim is that surgical masks do not protect against respiratory viruses. This is not true. Several peer-reviewed studies in medical journals have found that correct and consistent use of surgical masks in household or community settings conferred a significant degree of protection against influenza, severe acute respiratory syndrome and other respiratory virus infections, especially when combined with hand hygiene.
Another misconception is that surgical masks should only be worn by symptomatic individuals. In fact, surgical masks are effective when worn by both respiratory virus-infected persons and their contacts. Furthermore, it is well recognised that even asymptomatic Covid-19 patients can still be infectious to others, rendering this recommendation inapplicable to the current pandemic.
Like other respiratory viruses, Sars-CoV-2, the virus causing Covid-19, is largely transmitted by droplets from infected persons. Therefore, the scientific evidence in favour of mask use against other respiratory viruses is generalisable to Covid-19.
