26 April 2020
Simon Thornley, epidemiologist with the Covid Plan B Group, says parents who need to send their children to school this week should not be fearful, as the chance of exposure to Covid-19 is very low and their chance of being harmed if they catch it is extremely small.
Thornley says in a post to the Plan B website that the risk is not the same for everyone.
“Your risk of dying from the virus is about the same as your risk of dying that year given your age.
“This means that children of school age are extremely low risk for having severe complications from the virus.
“It is very sensible for the government to open schools. I believe that this will help build higher levels of immunity in children to act as barriers for the spread to elderly and those with pre-existing medical conditions. These people are the ones we really want to protect from the virus.
“Modellers have concluded that school closures are unlikely to be an effective strategy for halting Covid-19.”
In a systematic review of scientific studies relating to Covid-19 in children, the authors concluded that children had a much milder response to the virus than for adults. Of three children that required intensive care, all had severe underlying conditions.
In one case-series in China, 90% of test-positive cases had no symptoms attributable to the virus. Of all children, infants are more likely to have severe complications.
One possible objection to returning to school is that adults could catch the infection from children.
“While this is possible, an analysis of cases from Shenzhen, China, shows that attack rates are higher in older adults and the majority of transmission occurs among household contacts.
New Zealand has had a Covid-19 cluster of about 92 students at Marist College in Mount Albert, Auckland. The first identified case was a teacher and 12 students have subsequently tested positive. The majority of cases have been adults and at the time of writing, 79 cases had recovered.
In New Zealand, there is little evidence of risk from spread of infection in children. According to the Ministry of Health, there were 18/344 or 5% of New Zealand’s active cases in people under the age of 20 years. Overseas data shows that immunity to the virus is building in populations that have been tested.