COVID-19: Ventilation crucial in schools as Kiwi kids return - experts

Thousands of New Zealand children are heading back to school on Thursday, with facemasks recommended - but not compulsory - and additional hygiene measures in place.

"[It's] just going over those things about getting too close to each other, not playing close games and things like that," said Shane Buckner, the principal of Wairakei School in Christchurch.

With all of New Zealand outside of Auckland at COVID-19 alert level 2, schools outside the super city have reopened. Canterbury's Kaiapoi North School principal Jason Miles told The AM Show they're ready to go.

He admitted he doesn't expect many of his students to wear masks, something that's not required but "strongly encouraged" for children aged 12 and over.

Children aged 12 and under - the majority of Miles' students - do not have to wear masks anyway.

"We'll be focusing on the good hygiene practices such as washing hands, drying hands, using sanitiser and making sure our buildings have great ventilation through them," he said.

And experts say good ventilation is exactly what schools should be focusing on, with aerosols now considered the dominant form of COVID-19 transmission.

"Ventilation strategies should work together with other outbreak control measures such as mask-wearing... staying home when unwell and vaccinating staff and students," said Julie Bennett, a senior research fellow at the University of Otago Wellington's Department of Public Health. 

With mounting evidence good ventilation is crucial, Dr Bennett said practical guidance on ventilation is needed for education providers. 

At the very least, teachers need to open the windows, experts have said.

"Optimising ventilation in schools has multiple co-benefits aside from COVID-19 prevention, including prevention of other respiratory infections that circulate in schools and improving children's learning and concentration," Dr Bennett said, adding "ventilation in schools should be a critical component of the New Zealand COVID-19 response to keep children safe and schools open, as schools do far more than provide formal education".

Starship Children's Hospital developmental paediatrician Jin Russell said while there's been a lot of focus on masking, she agreed improving ventilation is also a critical measure.

"Evidence shows that by implementing combinations of interventions, such as universal masking, improving ventilation, increasing activities outdoors… distancing, hygiene, and staying at home if any symptoms, schools can significantly reduce [the] potential transmission of the virus and keep everyone protected."

There have been only a few cases of COVID-19 reported outside of Auckland - 15 in Wellington - during the Delta outbreak.