Younger Age Groups Are More Vulnerable to the Omicron Variant

After the Spread of the Omicron Variant, COVID-19 Transmission Rate in Ages 10-19 Increased About 5 Times
Omicron Variant Infects Upper Respiratory Tract More Easily Than Lungs, Greatly Affecting Children

[Asia Economy Reporter Yoon Seul-gi] A study has found that the probability of infection with the Omicron variant is about five times higher than with previous viruses such as the COVID-19 Delta variant among the 10-19 age group.

On the 27th, according to the medical community, Jun-young Jeon, an infectious disease specialist at the National Cancer Center, and Yong-dae Kim, a professor in the Department of Statistics at Seoul National University, reported that after the spread of the Omicron variant, infections among those aged 10-19 increased by about five times.

The research team investigated the degree of infection by age group according to the type of prevalent variant, based on mathematical infectious disease transmission models, during the third wave before the Delta variant occurred in Korea (October 15 to December 22, 2020), the fourth wave caused by the Delta variant (June 27 to August 21, 2021), and the fifth wave earlier this year (January 1 to 31, 2022).

To exclude the effects of vaccination, the team applied vaccination rates and the decline in vaccine efficacy over time to the model, then analyzed how much the transmission speed differed by age group in each wave.

The study found that among those aged 10-15, the transmission speed of COVID-19 after the spread of the Omicron variant was 5.28 times higher compared to the period before the Delta variant emerged. Similarly, those aged 15-19 showed a fivefold increase. In contrast, those aged 50 and above showed about a twofold difference, and those over 75 showed only a 1.12-fold difference, indicating little change.

Compared to the Delta variant, the transmissibility of the Omicron variant was higher in younger age groups; among those aged 10-19, the transmissibility was 3.21 times higher, whereas for those over 75, it was 0.93 times lower.

Previously, after the spread of the Omicron variant, hospitalization rates among adolescents in the United States and the United Kingdom increased more than threefold. Overseas researchers have diagnosed that the Omicron variant infects the upper respiratory tract more easily than the lungs, which may affect children with immature upper respiratory tracts more significantly.

Regarding this, the research team explained that the adaptive characteristics of COVID-19 can be observed, noting that the vulnerability of younger individuals to the Omicron variant is similar to that of influenza (flu). The team stated, "It is not certain whether children will become the core group for COVID-19 transmission, but to reduce the overall impact on the community, it may be worth considering putting more effort into vaccinating children."

This study was published on the 23rd in the international academic journal BMC Medicine.