With some schools around Australia set to reopen during the second school term, debate has reignited as to whether school staff, students and their families are at risk, and whether measures to halt the spread of coronavirus will be jeopardised.
When the epidemic began, there was no evidence about the cost-benefits around shutting schools specific to Covid-19 because, being a new virus, it had not been studied before. Epidemiologists, virologists and governments relied on data from other viruses, such as influenza, to assess whether or not schools should close. By 18 March, more than 100 countries had implemented school closures. Some, like New Zealand, closed schools early, whereas Sweden kept its schools, and its borders, open.
But a few months into the pandemic, what does the evidence say about schools?
‘Very limited’ spread
On Sunday, New South Wales Health’s Centre for Immunisation Research and Surveillance (NCIRS) published its findings after researchers followed up all close contacts of Covid-19 across 10 of the state’s high schools and five primary schools. Researchers collected Covid-19 test data from all 863 close contacts of the nine students and nine staff infected. They found it was likely, but not certain, that two students and no adults had been infected at school as a result of those infections.
“The findings from this detailed investigation are preliminary,” the study concluded. “However, they do suggest that spread of Covid-19 within NSW schools has been very limited [and] appears considerably less than seen for other respiratory viruses, such as influenza. In contrast to influenza, data from both virus and antibody testing to date suggest that children are not the primary drivers of Covid-19 spread in schools or in the community.”
Epidemiologist Dr Kathryn Snow, from the University of Melbourne’s Centre for International Child Health, said it was important to emphasise there is a difference between a child’s likelihood of catching the virus themselves and their likelihood of passing the virus on to others. Evidence showed children were less likely to pass it on than adults but that did not mean scientists were saying children could not become infected.
“Many parents and teachers are finding the debate about schools confusing and stressful,” Snow said. “The evidence shows that although primary school aged children can catch Covid-19, they usually only experience a mild illness. Interestingly, although primary school aged children can definitely catch it, it seems that they almost never pass the virus on to anybody else.
“This will be counter-intuitive to a lot of parents, who know that children often bring home other germs from school. However, we see this same phenomenon with other diseases as well, for example with tuberculosis.”
She added that transmission from children is only one piece of the puzzle in terms of whether schools should be open.
“There is also a risk of transmission between teachers and parents, and from teachers to students. Some teachers are in their 60s and could be at risk of a serious illness if they were to catch Covid at work. Globally, there have been some outbreaks among parents, teachers, and students linked to schools and school functions.”
Support for the disadvantaged
But schools being closed will have a disproportionate impact on some students, especially students with learning difficulties or those with limited IT resources at home, she said. “As a health equity researcher, I’m personally quite concerned about the impact on some students from disadvantaged backgrounds.”
Students returned to schools in South Australia on Monday, but parents who chose to keep their children at home reported widespread issues with the online learning system called LearnLink. The Australian Capital Territory and Victoria will deliver their curriculum via online and remote learning for term 2, while students face a staggered return in NSW from Wednesday. WA schools are open for term 2, with year 11 and 12 students especially encouraged to attend.
Researchers led by London’s University College undertook a systematic review of the effectiveness of Covid-19 related school closures globally, with their findings to be published in the May edition of the international medical journal the Lancet. The researchers examined data from nine published studies and seven non-peer-reviewed studies on school closures and Covid-19. Only one study the researchers reviewed examined school closures as a separate intervention to other measures, finding the impact of closing schools on transmission rates was marginal.
“There are few data available from the literature on coronavirus outbreaks to guide countries on the use of school closures or other school social distancing practices during the Covid-19 pandemic,” the researchers concluded.
“Available evidence is consistent with a broad range of impacts of school closures, from little effect on reducing transmission through to more substantial effects. Yet, the economic costs and potential harms of school closure are undoubtedly very high.”
The researchers added that education is one of the strongest predictors of the health and the wealth of a country.
“Policy makers and researchers should also look to other school social distancing interventions that are much less disruptive than full school closure and might substantially contribute to maintaining the control of this pandemic,” they concluded. “Although strong evidence is not available for the effectiveness of these practices, they might be implementable with much less disruption, financial costs, or harms.”
Reopening with conditions
A paediatric infectious diseases specialist with Perth Children’s Hospital, Dr Asha Bowen, said there was good evidence that children and adolescents have a lower rate of infection with Covid-19 than adults, and when infected, had a milder course of symptoms. She said the study of NSW schools supported this.
“The transmission patterns are on the whole from adult to child within household studies (90% of cases), confirming that children are more likely to be infected by an adult than another child,” Bowen said. “The health evidence supports children and adolescents being back in schools with reopening of schools occurring in term 2 in Australia.”
Epidemiologist and infectious disease physician with Alfred Health and Central Clinical School, Dr Allen Cheng, said the evidence so far suggested schools should be reopened, but with some important caveats.
Schools need to make sure there are precautions in place to ensure good hygiene, that physical distancing is carried out, and that policies to identify and respond to any cases were in place, he said.
“Beyond those purely epidemiological considerations, there are obviously other factors that are important – that teachers feel confident that they are safe and that parents feel their children are safe.”
On Friday, the chief medical officer Prof Brendan Murphy insisted there is no need for social distancing in classrooms. The official advice from the Australian Health Protection Principal Committee states “it is of utmost importance that teachers and parents alike maintain physical distancing between themselves and each other at school”, given adults are at higher risk of passing on and acquiring infection. The committee said children and teachers must not go to school if unwell.
“There are many outbreaks that have been described – weddings, business meetings, religious gatherings, workshops – all relating to adults interacting together, and schools are notable in their absence from this list,” Cheng said.
Professor Kristine Macartney, the director of NCIRS and leader of the NSW schools study, said she understood the discussion and concerns in the community around reopening schools.
“But our study isn’t a model,” she said. “This is real world data, showing what has actually happened. And we know education is critical for children and with conditions in place, they should be returning to school.
“What we don’t know yet is why children aren’t getting infected and passing it on at the rate of adults. We see children so highly affected by influenza, for example. It undoubtedly has something to do with how the virus interacts with cells that lie in our respiratory tract and the way the immune system of young people responds. But the exact mechanism underpinning that and the milder infections we see in children, we just don’t fully understand.”