In the debate about the reopening of schools during the coronavirus pandemic, the question of how contagious children and adolescents are is particularly high. A study from South Korea found evidence that adolescents between the ages of 10 and 19 passed the virus on at least as often as adults. Children under the age of ten, on the other hand, were only half as often infected by another person.
The results can be on the CDC’s “Emerging Infectious Diseases” journal. The research team led by Eun Kyeong Jeong of the Korea Centers for Disease Control and Prevention in Cheongju identified a total of 5706 so-called index cases in which Covid-19 appeared without any further known contact. Based on these cases, the researchers monitored all 59,703 contacts in index cases for coronavirus infection. They distinguished between people living in the same household as the index case and external contacts.
Of the 10,590 in-house contact persons, a total of 11.8 percent were also infected after the end of the observation period – they were presumed to have been infected by the index case. Of the 48,481 external contacts, 1.9 percent fell ill. Again, it can be assumed that the infection is due to the index case.
The comparison of age groups was quite striking. Infected children under the age of ten infected only just over five percent of their household members. Infected adolescents between the ages of 10 and 19, on the other hand, 18.6 percent. From this, the scientists conclude that adolescents are at increased risk of passing the infection.
The data was collected during the South Korean school closures. It is quite possible that young people in particular maintained private contacts and thereby reduced the effect of the closures, the researchers argue. However, they do not have any concrete indications of such an effect. The fact that adolescents passed on the virus more often could simply be due to the fact that they maintain closer relationships with a variety of other people and interact with them more intensively than adults.
The study, with a relatively large number of participants studied, gives a good picture of the infection situation in South Korea from January to March 2020, the researchers write. However, the proportion of under-19s was relatively small, with 153 of the 5706 first-time infected. How meaningful the statistics really are and which cases may have been overlooked because only people who showed symptoms were tested outside households cannot be said at this stage. Nevertheless, Ashish Jha, the director of the Harvard Global Health Institute, praised the study to The New York Times, calling it careful, comprehensive and “one of the best on this subject we have so far”.