New long-term modelling shows effectiveness of consistent mask-use

Modelling the effectiveness of wearing a mask to prevent contracting COVID-19 over a 12-month period indicates there are benefits to consistent mask use, University of Melbourne researchers have found.

The research team used a model to simulate the population of Victoria and investigated whether the likelihood of being infected with the SARS-CoV-2 virus was reduced by wearing a mask at all times outside of the home.

The findings, published in the Medical Journal of Australia, indicate consistent mask use in the community is more effective at reducing COVID-19 infection and mortality burden, than waiting for a spike in cases or new wave of infections before wearing a mask.

Co-author Samantha Howe, PhD student in the Centre for Epidemiology and Biostatistics in the Melbourne School of Population and Global Health, said that these findings can be compared to the research team’s previous modelling published in The Lancet Regional Health in January, which found that simulated mask mandates introduced only during large epidemic waves had minimal impact on COVID-19 infections and deaths.

“The findings of the present study indicate that more consistent mask use rather than waiting until there is a large wave of COVID-19 cases is more effective at reducing COVID-19 burden in the population,” Howe said.

“For example, participation in mask use by half of the population, compared to none, resulted in 25 per cent fewer deaths over 12 months.”

Howe said the results could help inform mask policy in the future.

“If a highly virulent variant of SARS-CoV-2 were to emerge in the next year or so, our modelling supports widespread mask wearing throughout the wave – not just at the peak of the wave,” Howe said.

The modelling also suggested that – at least with a one-year time horizon – more deaths are prevented if all age groups are wearing masks, not just the elderly.

“However, given population fatigue with wearing masks, wide public compliance with mask wearing may simply not be achievable,” Howe said.

“Future modelling of mask wearing among those with co-morbidities and immuno-suppression, or in high-risk settings, may help to identify targeted strategies that are effective.”