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University of Otago staff wear respirator (N95) masks. Credit: Luke Pilkinton-Ching

University of Otago staff wear respirator (N95) masks. An international review has found masks are effective in reducing the transmission of respiratory infections. Credit: Luke Pilkinton-Ching

Medical researchers from the University of Otago, Wellington, are calling for Aotearoa New Zealand to update its face-mask policies, after an international review found masks are effective in reducing the transmission of respiratory infections.

Associate Professor Amanda Kvalsvig and Professor Michael Baker, of the Department of Public Health, are part of an interdisciplinary team of 13 researchers who conducted what is probably the most extensive review of masks so far published.

Led by University of Oxford’s Professor Trisha Greenhalgh, researchers reviewed scientific evidence on the transmission of COVID-19 and other respiratory pathogens, reanalysed randomised controlled trials of masks, and examined more than 400 peer-reviewed studies.

Their findings, published in the high-impact journal Clinical Microbiology Reviews, show masks – in particular respirators – are effective in reducing the transmission of respiratory infections.

Associate Professor Kvalsvig says indoor air quality is generally poor in workplaces, transport, and other public settings in New Zealand, allowing viruses to spread easily during the winter months. Masking in these settings can help people to avoid catching infections and passing them on. Their use can also reduce COVID-19 reinfections that are driving the rise in Long Covid.

“The benefits of wearing a mask have been hotly debated over the past few years,” she says.

“The findings of this rigorous review and reanalysis put an end to that uncertainty. We now have a clear pathway to action, including reducing the number of respiratory infections in winter 2024. Masks can also provide effective protection in a public health emergency, for example if avian influenza (bird flu) starts to spread between humans.”

An important implication of the review is that New Zealanders need better access to effective masks. Cloth face coverings and disposable medical masks can help reduce infection risk, but respirators such as N95 and FFP2 provide a significantly higher level of protection.

Professor Baker says New Zealand needs to update its policy and practice on mask use.

Infection Prevention and Control policies are needed in four areas: personal protection of at-risk groups, protection in specific settings including workplaces and healthcare facilities, protection for seasonal respiratory infections, and protection for pandemics, he says.

“Updating our policies will allow all New Zealanders to benefit from the effective and versatile protection that masks provide against seasonal, epidemic and pandemic infections.”

While no serious harms from masks or respirators were identified, the review highlights some downsides, such as inconvenience and discomfort. Masks can also make communication difficult for D/deaf and hearing-impaired people.

However, Associate Professor Kvalsvig, who is deaf and a lip-reader, says that the review also identified practical solutions to these difficulties.

“We need to see these challenges as a call to action,” she says.

“By investing in better design, more inclusive policies, and clearer communication, we can optimise masks for real-world use and ensure that everyone can benefit from this valuable public health protection."

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