Covid-19 is a top-10 killer of US children, and a US expert says New Zealand should learn from their experience and adopt classroom surveillance testing.
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Speaking to Checkpoint, Covid-19 testing expert Dr Gigi Gronvall from Johns Hopkins Centre for Health Security said surveillance testing in schools could help keep the virus in check as well as reassuring families it is safe for kids to head back to class.
Primary school children in Auckland can head back to face to face classes tomorrow, although some schools are staggering in-school days and limiting attendance to maintain social distancing.
Others will hold classes in the open air or with windows and doors open to make sure classes are well ventilated.
Covid-19 vaccinations are currently only available to those aged 12 and over.
Dr Gronvall has been tracking Covid-19 testing practices throughout the pandemic.
She said even with high vaccination rates, there is still a place for surveillance testing.
"Testing is very important to limit spread and also for people to feel confident in going about their daily activities. Testing is important for... schools, for your unvaccinated populations... it could play a really big role there.
And she said the effects of the virus on children who have become sick has been devastating.
"A lot of people correctly think of Covid as being a disease of adults, and that is true - that they [experience] the most devastating immediate impacts - I would not dismiss the impact on children.
"Here in the US ... there are a lot of children that end up in the hospital and it is a top 10 killer of children in the United States."
Gronvall said where she lives 'pool testing' had been particularly important in schools to detect any hidden cases.
Pool testing or batch testing is a long-standing method for efficiently testing large groups of people. One sample is analysed that contains sample material from everyone in a group - in this case from everyone in a classroom.
"All the kids swab their noses and then the swabs go into one tube," she said.
That single combination sample is analysed with one laboratory test, and if even one person from the group is positive it should show in the results - and individual testing would then be done.
"It's been very effective at limiting spread, it's also very effective at giving confidence that there isn't spread going on in the school," Gronvall said.
"Every classroom has one pool test, and so you know if the classroom is positive or negative after a day or two."
Associate Professor Gigi Gronvall Photo: Supplied/ John Hopkins University
In Gronvall's area, pool samples are taken from classes of about 30 children.
The children can swab their own noses, and "they make songs about it for the littler kids," she said.
In some US high schools, children who are vaccinated and have been close contacts of someone with Covid-19 are now no longer being quarantined, but are being given rapid antigen tests every day.
"That's called 'test to stay' ... they test them every day, and the rapid antigen tests are really good at determining if you have a lot of virus in your nose at that time.
"If you're testing somebody everyday and they don't have a lot of virus in their nose, then they're not contagious. So if you do become positive on those kinds of tests you need to be isolated immediately."
Gronvall said only about two percent of close contacts in US schools have turned out to be positive so far.
This meant that quarantining all close contacts en masse meant a lot of children were being quarantined unnecessarily, she said.
"The whole idea of test and stay is to try and allow those kids to stay in school so they're not missing out, and just concentrating on testing to make sure they're not actually infected."
Experts have highlighted ventilation strategies to reduce the risk of transmission of Covid-19 in enclosed spaces like classrooms. But New Zealand schools are largely relying on opening doors and windows to try to improve ventilation.
Gronvall said, as well as helping reduce the transmission of Covid-19, air quality improvements also reduce health risks from flu, RSV and other 'respiratory nasties'."
"HEPA-filtered portable devices are a really great way to increase the filtering of the air. And in some places you can't open the windows - or if it's too cold you can't open the windows either."
"That's been something that a lot of schools here have used, and it's been very effective. I hope that it stays post-Covid, because none of those disease are all that fun either, so it would be great to be able to cut down on all of them."