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Public Mask Wearing: Does it work?

Face mask wearing in healthy people is controversial in western cultures partly due to the association with masks and illness. The science behind mask wearing is sound - but can face mask wearing work on a public wide scale? In Hong Kong Special Administrative Region (HKSAR), they’ve proved exactly that!

Scientific article summary by Niamh Mortimer.

Countries that practice community-wide face masking have a significantly lower incidence of coronavirus disease 2019 (COVID-19) compared to non-masking countries.


Face mask-wearing among healthy people in the community is often seen as controversial in Western cultures – despite the evidence that it can reduce transmission risk in respiratory viruses.

Community-wide face mask-wearing was practiced by the general population in Hong Kong Special Administrative Region (HKSAR) at an early stage of the local COVID-19 epidemic.


This study aimed to assess the effect of community-wide mask-use to control COVID-19 in HKSAR.

Study Design

People presenting with respiratory symptoms at outpatient clinics or hospital wards were screened for COVID-19.

Epidemiological analysis was performed for confirmed cases.

The incidence of COVID-19 with community-wide masking in HKSAR was compared to that of non-mask-wearing countries that are comparable to HKSAR in terms of population density, healthcare, vaccinations and social distancing measures.

To calculate the incidence of mask wearing, 67 members of staff in hospitals around HKSAR, recorded the number of people not wearing face masks among the first 50 people they encountered in the morning between 7 and 9am.

They continued this over three consecutive days (6-8th April 2020).


Only 337 people (3.4%) did not wear a face mask – making the daily compliance of face mask usage 97.2%, 97.1% and 95.7% over the three days.

Within the first 100 days of the epidemic (31st December 2019 to 8th April 2020), 961 people were diagnosed with COVID-19 in HKSAR.

The incidence of COVID-19 in HKSAR (129.0 per million population) was significantly lower (P<0.001) than that of:

  • Spain (2983.2 per million population)

  • Italy (2250.8)

  • Germany (1241.5)

  • France (1151.6)

  • US (1102.8)

  • UK (831.5)

  • Singapore (259.8)

  • South Korea (200.5)

The compliance of face mask-wearing by HKSAR general public was 96.6%.


Community-wide mask-wearing may contribute to the control of COVID-19 by reducing the amount of infected respiratory droplets being emitted.

Universal masking in the community may mitigate the extent of transmission of COVID-19 and may be a necessary public health measure in densely populated cities.


Type of mask-wearing was not controlled.

The compliance of other infection measures was not controlled such as face touching and hand hygiene.

Could not count the mask compliance for every community setting.


Epidemiological - assessing how often the disease appears in a group of people.

Incidence - the number of people who develop a disease in a particular time.

Epidemic - widespread occurrence of infectious disease in a community at a particular time.


Cheng VC, et al. The role of community-wide wearing of face mask for control of coronavirus disease 2019 (COVID-19) epidemic due to SARS-CoV-2. Journal of Infection, 2020; 107–114. Published: 23 April 2020

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