Test, trace, isolate key to safe schools in COVID-19

By Dr. Ananya Mandal, MDAug 4 2020

A new Australian study shows the rate of transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) between children attending school could be minimal.

The study is particularly relevant because of the high rates of transmission of the virus across the world that have necessitated the closure of schools. As of today, there are over 18.38 million cases of SARS-CoV-2 infection around the world, which have taken nearly 700,000 lives.

The new study titled, "Transmission of SARS-CoV-2 in Australian educational settings: a prospective cohort study", is published in the latest issue of The Lancet Child and Adolescent Health. The study was funded by the New South Wales Department of Health.

Study: Transmission of SARS-CoV-2 in Australian educational settings: a prospective cohort study. Image Credit: Monkey Business Images

What was this study about?

Researchers led by Professor Kristine Maccartney from the National Centre for Immunization Research and surveillance, the Children's Hospital at Westmead and the University of Westmead, Australia explain that schools around the world have shut down to prevent the virus transmission. Still, no studies are looking at the actual risk of transmission of the virus among children should the schools reopen. Studies have shown that COVID-19 affects children with less severity, and generally, the illness is milder compared to adults.

The researchers write that "children are less likely to be the primary infection source in household clusters, compared with adults." They added that while school closures could help prevent the spread of viral infections such as influenza, such measures during the COVID-19 pandemic are not clear.  Closing schools, on the other hand, has "significant social and economic impacts on children and families" and affects national and global economies, they write.

In Australia, during the initial phase of the epidemic, schools remained open. However, attendance at this time remained poor. Australia's eight states and territories, including New South Wales (NSW), have kept schools open according to the national policy.

These schools observed precautions such as "physical distancing, hygiene measures, and educational facility cleaning." Online learning was initiated on March 23, 2020, and schools were open only for children who needed to be there, including children of health care and essential workers who had no other care options.

This is the first study that looks at the spread of SARS-CoV-2 infection among children and adults in schools and early childhood education and care (ECEC) settings. The authors conducted this study in the hope that findings could help policymakers, health-care providers, and the public to understand the risk of the spread of the infection among children.

What was done?

For this study all cases of COVID-19 that had been confirmed in the lab using RT PCR under the age of 18 were included. Adult cases who attended a school or ECEC setting were included. The study duration was between January 25 and April 10, 2020.

Adults and children attending schools or educational facilities while they were capable of spreading infection – i.e., 24 hours before the onset of symptoms were included. These were in accordance with the national guidelines.

For all the cases identified and their close contacts 14 days quarantine was mandated with monitoring of symptoms and testing for the virus. Nucleic acid testing and SARS-CoV-2 antibody testing in symptomatic and asymptomatic contacts were also offered. All secondary cases (cases infected by those attending schools and ECEC) were also recorded.

What was found?

For this study, the researchers included a total of 15 schools and 10 ECEC settings in the most populous state of NSW. From these 12 children and 15 adults were found to be infective while attending these institutions. These index cases had a further 1,448 contacts who were monitored and followed up.

Results showed

• 633 or 43.7 percent of the contacts of the index cases underwent nucleic acid testing, or antibody testing, or both.
• 18 or 1.2 percent of secondary cases were recorded.
• There were three children and two adults (5 out of 914 contacts in schools) who were secondary cases (this put the attack rate at 0.5 percent wrote the researchers).
• Among the 9 ECEC settings, there were 497 contacts; there were no secondary cases of infection.
• In one ECEC, there was a spread of infection to six adults and seven children. Here the secondary attack rate was 13 of 37 or 35.1 percent wrote the researchers.
• Overall there was 28 percent (5 cases) out of the 18 secondary infections that turned out to be asymptomatic. These five asymptomatic positive cases were three infants aged 1 year, one teenager aged 15 years, and 1 adult.

Conclusions and implications

The authors concluded that transmission of SARS-CoV-2 in educational settings was low during the initial wave of the epidemic in NSW among 1.8 million children.

The researchers concluded, "With effective case-contact testing and epidemic management strategies and associated small numbers of attendances while infected, children and teachers did not contribute significantly to COVID-19 transmission via attendance in educational settings."