A Burnet Institute study that concluded mask mandates significantly curbed the spread of COVID-19 has attracted a warning notice from the journal that published it. 

But the research group has defended its methods and findings, following the investigation by the open access journal PLOS ONE.

The 2021 study found that the proportion of mask-wearing Melburnians increased from 43% to 98% after the mask mandate was introduced in mid-2020, based on analysis of 44 photographs in The Age newspaper. 

The images were of 304 people in public places, excluding children and those who were eating and drinking, in the period before and after the mandate.