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Photo: Getty
Photo: Getty

SocietyApril 23, 2020

Siouxsie Wiles: What we know about children and Covid-19

Photo: Getty
Photo: Getty

A lot of people are very reasonably concerned about the implications of schools and early childhood education reopening. Siouxsie Wiles explains what the latest studies can tell us about the risks.

When Aotearoa New Zealand heads to alert level three, schools and early child education centres will be opening again. They will only be available for those children up to Year 10 whose parents aren’t able to keep them home.

I’ve received lots of messages and questions from concerned parents and teachers. Is having kids back at school, daycare or kindergarten the right thing to do? Aren’t children just going to spread Covid-19 back to their bubbles?

These are all excellent questions. Thanks to a review of the literature by Dr Alasdair Munro and the Don’t Forget the Bubbles team in the UK, I can fill you in on the latest studies and provide some answers.

How often do children get Covid-19?

Not very often. Which is surprising, as kids and older people are usually the most vulnerable to getting sick. The first data we had showing this came from the WHO’s Joint China Mission investigating the outbreak in Wuhan. They found that Covid-19 in children seemed to be relatively rare. Just 2.4% of the total reported cases were in those under the age of 19. A recent analysis of over 149,000 laboratory-confirmed Covid-19 cases in the US showed children and young adults under 18 made up just 1.7% of those cases. In Italy it was 1.2% and in Spain 0.8%. In Japan it’s been reported to be 3.2%.

Here in New Zealand, 10.2% of our confirmed and probable cases have been people under the age of 19. Half of those were aged 15-19. The 10-14 year olds have made up 2.8% of our cases. For those aged between 5 and 9 it’s 0.9%, and for those under 4, it’s 1.4%.

Interestingly, those numbers are even lower when we look at confirmed cases only: 0.45% for under 4s, 0.18% for 5-9s, and 2.25% for 10 to 14 year olds. See Chris McDowall’s chart below.

What happens to those children that do get Covid-19?

They mostly get a mild infection. Some children have had a more severe infection. From the WHO Joint China Mission, 2.5% had a severe illness and 0.2% critical disease. Globally, a small number of children have, tragically, died. In other words, it’s very rare for children to be badly affected by Covid-19, even if they have underlying health issues.

While we’re still not quite sure why, the virus that causes Covid-19 is a coronavirus. So in the same way that children’s immune systems are very good at fighting off other coronaviruses, they seem to be very good at fighting off this one too.

Are children likely to be playing a big part in spreading Covid-19?

Surprisingly, the evidence suggest not. One worry was that children with mild symptoms or no symptoms at all might be spreading the virus without us realising that. But testing of the general public in Iceland and Italy suggests this isn’t the case. I wrote about the Icelandic study here. Of the 848 children under the age of 10 who were tested, none tested positive. In Vo in Italy, they swabbed 70% of the residents of the town. Again, none of the 234 under 10s tested positive, despite some of them living with people with Covid-19.

Another study which looked at data from China, Singapore, South Korea, Japan, and Iran and identified 31 household transmission clusters. Just three of these had a child as the index case. During the WHO Joint China Mission, people interviewed by the team could not recall any cases where Covid-19 was spread from a child to an adult.

What about the Marist cluster?

Marist College is a Catholic secondary school for girls in Auckland. It is one of our largest clusters, with 93 cases to date. It’s important to remember that just because it is known as the Marist cluster, that doesn’t mean all the cases are in children from the school or that children were involved in transmitting the virus. Ashley Bloomfied has confirmed that it did not begin with a student. A large portion of those affected are teachers, parents, and their families and they could have become infected through social events or other contact. Remember, we also had a teenager at a Dunedin school test positive and that didn’t turn into a large cluster.

Should we be testing children and only letting them go to school if they are negative?

No. I don’t think this is a good strategy. Getting swabbed for the Covid-19 test is not pleasant, especially for little kids. And remember that a negative test will only tell you the person was negative when they were tested. They could be incubating the virus and test positive a few days later. This kind of testing is not a good use of our resources when there is so little evidence that children play a big role in the spread of Covid-19.

This story was updated on April 23 to correct statistics on the proportion of NZ Covid-19 cases who are children.

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Director of health Ashley Bloomfield (Illustration: Simon Chesterman)
Director of health Ashley Bloomfield (Illustration: Simon Chesterman)

SocietyApril 22, 2020

Covid-19: New Zealand cases mapped and charted, April 22

Director of health Ashley Bloomfield (Illustration: Simon Chesterman)
Director of health Ashley Bloomfield (Illustration: Simon Chesterman)

The latest in our series of charts, graphics and data visualisations by Chris McDowall. David Garcia helped create today’s charts.

This work is made possible thanks to donations from The Spinoff Members, with support from the Science Media Centre

These posts collate the most recent statistics and present them as charts and maps. The Ministry of Health typically publishes data updates in the early afternoon, which describe the situation at 9am on the day of release. These data visualisations are interactive; use your mouse or thumb to hover over each graph for more detail.

Note for users of The Spinoff app: if the charts below are not appearing, please update your app to the latest version.

This afternoon’s Ministry of Health figures report that the total number of confirmed and probable Covid-19 cases stands at 1,451. There are now 1,036 people reported as having recovered – an increase of 30 on yesterday, meaning there are now 401 active cases in New Zealand. There were six new cases reported in the last 24 hours, all confirmed by testing.

There was one further death reported, a woman in her 70s who had been living at the Rosewood home in Christchurch.


The above chart compares active and recovered cases. Active cases are confirmed or probable cases of Covid-19 where the person has neither recovered nor died. Recovered cases are people who were once an active case, but are at least 10 days since onset and have not exhibited any symptoms for 48 hours.

Since April 8, we have seen an overall downward trend of active case counts.

Laboratories yesterday processed a record number of tests, with 5,289 completed. That brings the total number tested to date to 94,797, with the seven-day rolling average 4,043.

The symbol map above shows confirmed and probable Covid-19 cases arranged by district health board. Hover over the blue circles for more details.

A significant cluster is defined by the Ministry of Health as “when there are 10 or more cases connected through transmission and who are not all part of the same household”. It includes both confirmed and probable cases. There are still 16 significant clusters. Five more cases of Covid-19 have today been connected to clusters. There are eight clusters that have not had a new case reported in the last seven days.

This chart shows cases by the date they were first entered into EpiSurv, ESR’s public health surveillance system. Note that the number of cases reported on a particular date may not match the number of cases reported in the last 24 hours. This is because the number of confirmed and probable cases reported in the last 24 hours includes cases that were entered on an earlier date as “under investigation” or “suspected” whose status has now been changed to confirmed or probable.

To view previous days’ charts, see here. For the latest on the Covid-19 outbreak in New Zealand, go here.