Study finds masks did not reduce COVID-19 for children aged 10-12

Mandatory mask rules in Finnish schools did not reduce COVID-19 incidence among 10-12 year olds, according to a study by researchers from the Finnish Institute for Health and Welfare.

The study published in BMC Public Health found masking younger children had no additional effect on COVID-19 infections.

Statistician and lead author Aapo Juutinen told Cosmos that, like in many Australia states, mask mandates were introduced during the Northern Hemisphere’s Autumn 2021 as a response to the worsening pandemic situation. 

“Despite a lack of clear understanding regarding the effectiveness of face masks in school environments, mask mandates were viewed as a relatively simple intervention to control the spread of the virus. School lockdowns had already been implemented during the spring of 2021, and many believed it was crucial to keep schools open while taking appropriate measures to ensure the safety of students and staff,” Juutinen said.

Cities like Helsinki and Tampere mandated face mask use for ages 12 and above. Others like Turku expanded the mandate to younger children, including ages 10-12.

The study compares the 14-day rates of COVID-19 per 100,000 children aged 10-12 in Turku, Helsinki and Tampere.

The three cities were selected because their baseline COVID-19 rates were similar in August and September 2021 before the mask mandates were introduced. 

Mask mandates for children aged 10-12 were introduced in Turku in mid-October with some local variation, and applied across the entire city from 11 November 2021. Whereas Helsinki and Tampere did not mandate masks for this age group.

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Moving averages of observed 14-day COVID-19 incidences per 100 000 inhabitants (dashed line) and modelled 14-day COVID-19 incidences per 100 000 inhabitants (solid line) in 10–12-year-olds in Helsinki and Tampere (face masks not mandated in schools in this age group) and in Turku (face masks mandated) / Finnish Institute for Health and Welfare

The researchers undertook statistical analyses for age groups of 7–9 years, 10–12 years and 30–49 years, with 10–12-year-olds being the most relevant group due to the experimental design. 7–9-year-olds were included in the analysis as a control group, representing pupils attending same schools as 10–12-year-olds, but without a mask mandate, and 30–49-year-olds representing the parents of children, the paper said.

While the researchers say they could not completely account for all confounding factors, the three cities were generally similar in other respects, such as school guidelines and vaccination levels among adults.

“No specific kind of masks were mandated among the children. However, surgical face masks were the most used face mask type at the time.”

“Mask mandates were applied to the teachers as well,” Juutinen said by email.

In Finland at the time, school children throughout the country were recommended to be tested for COVID-19 even with minor symptoms. 

The study found Turku had the highest rates of COVID-19 for ages 10-12 for most of the time period analysed. It concludes face mask mandates did not reduce COVID-19 incidence among 10-12 year olds in Finland.

The study builds on the understanding of the effectiveness of COVID-19 measures in schools. In February, Cosmos reported on Victorian government analysis and data about the effectiveness of mandatory masks in schools. 

Juutinen said, “we will continue our research since there is still a lot to learn about the COVID-19 and I hope that our work supports evidence and science-based policy making.“

Read more Cosmos coverage on COVID-19 schools measures:

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