Face masks reduced spread of COVID-19 during first wave

Article written by Gary Finnegan.

Face masks likely played a role in reducing the spread of SARS-CoV-2 in Italy during the first half of 2020, according to a new study by mathematical modellers. The research, published in Infectious Diseases, shows that the use of face coverings could have reduced the number of official COVID-19 cases in Italy by up to 30,000 during spring 2020.

‘We found an excellent correspondence between nationwide lockdown and the peak of the epidemic in late March 2020, suggesting that this measure is the main factor in stopping the spread of the virus,’ said lead author Dr Morten Gram Pedersen at the Department of Information Engineering of the University of Padova.

‘Surprisingly, we identified further drops in viral transmission in mid-April 2020 within certain regions, which corresponded well with the provision of free face masks and/or their mandatory use,’ he added. ‘We did not see this reduction in places that did not introduce any additional local interventions at that time.’

The researchers used mathematical modelling to compare official data from eight demographically similar Italian regions that had introduced specific local control measures at different times – or did not impose any additional restrictions beyond the national rules. Each region was effectively isolated from the rest of the country during the nationwide lockdown, making regional comparisons even more relevant.

‘We found a change point reflecting a peak in the number of new cases for all eight regions that correspond well with the lockdown imposed between the 8th to 11th March 2020 depending on the region,’ said Pedersen. ‘Five of the eight regions showed further change points during April 2020 that corresponded well with the introduction of additional general containment measures, mandatory face mask use and/or distribution of free face masks.’

The team explored alternative explanations for the accelerated decline in new cases in late April 2020 in these regions, including the activity of people using public data from Google and weather conditions. But they found that none of the investigated alternatives could account for the acceleration of the end of the first wave of the COVID-19 epidemic.