Older children as likely to spread COVID-19 as adults, finds South Korean study

As a debate rages on over the reopening of schools and educational institutions around the world, a large study has found that children between the ages of 10-19 are just as likely to spread the COVID-19 infection as older adults.

The large-scale study—carried out in South Korea—analysed reports for nearly 60,000 contacts of 5,706 COVID-19 index patients in the country between January and March 2020.

The study found that infected children younger than 10 years aren’t even half as likely to spread the virus as adults, but among older children, the likelihood was just as strong. The study, titled “Contact Tracing during Coronavirus Disease Outbreak, South Korea, 2020”, concluded that reopening schools with this knowledge would mean a greater risk of infection and that the disease would spread among children faster than at the community level even.

Schools, colleges, universities and other educational institutions have been ordered to remain shut around the world in the wake of the new coronavirus infection, which first broke out late last year in China. However, after months of institutional lockdowns, some countries have started easing the restrictions, while others have asked for such educational institutions to be reopened.

The findings of the study are in contrast to past studies that had indicated that the rate of infection spread among children was not as high as among adults. But according to Dr Ashish Jha, director of Harvard Global Health Institute, those studies “were either small in scale or were flawed”. The new study, he said, is more accurate due to the methodologies involved as well as the number of people included in the cohort.

In this study, researchers from South Korea included 5,706 people infected with COVID-19 who had developed symptoms in their homes between 20 January and 27 March. This was the time when schools in South Korea were closed due to the rapid spread of the disease in the country.

After identifying these people, researchers traced 59,073 people who came in contact with them through contact tracing. People living in each patient's homes were also tested. While doing so, it was not seen who among them had the symptoms of the disease and who didn’t. However, contacts outside the home were only tested if they had the symptoms of COVID-19.

The rate of transmission and the likelihood of older children spreading the infection further needs to be factored in when charting out prevention plans for COVID-19.

The researchers could not ascertain whether the people who had developed symptoms of the viral infection were also the first ones to be exposed to the virus. At the same time, COVID-19 symptoms in children were less frequent than in adult patients. On this, the study did not properly assess the transmission chain in children.

The results of the study made it clear once again that the ability to spread infection in children under 10 years was not even half as likely as in adults. But older children were likely to spread more infections when schools reopen, and may even play a role in community transmission.

Health experts say that the role of asymptomatic young people infected should not be ignored. Epidemiologist Caitlin Rivers of Johns Hopkins Bloomberg School said researchers in the study have only traced children ill with COVID-19. According to her, it was not known how much virus was spread by children who did not show symptoms of the disease.

The latest study comes as a kind of breakthrough in analysing the patterns of the spread of infection in children, and middle and high school level or older children being able to spread the disease just as much as adults. Like adults, older children may also have poor sanitation habits and their social life may also be like that of adults.