Even with high vaccination coverage, continually introducing cases through relaxed quarantine is likely to lead to outbreaks that require public health responses. However, greater vaccine coverage provides a variety of response and control options.
Objective:
The effectiveness of masks in community settings is difficult to estimate because:
- often they are not mandatory (hence the uptake of masks is not an immediate change, making impact difficult to measure);
- limited information is available about actual mask uptake; or,
- masks are introduced at the same time as other control measures making it difficult to disentangle their impact.
Therefore we aimed to assess the impact of a mandatory mask policy that was introduced in Melbourne on 22 July 2020, outside of any other major policy changes.
Findings:
Using a statistical model, we found that there was a 22-33% reduction in the average Reff across all of Melbourne that correlated with the timing of the introduction of the mandatory mask policy, and could not be explained by other variables.
This mandatory mask use policy substantially increased public use of masks, and was associated with a significant decline in new COVID-19 cases after introduction of the policy.
First published: Jul 21, 2021
Burnet Institute
The Burnet Institute is an Australian medical research institute that combines medical research in the laboratory and the field, with public health action to address major health issues affecting disadvantaged communities in Australia, and internationally.
