An economist in Belgium has created a chilling new graph which shows younger people may not be tested for the COVID-19 coronavirus because they are asymptomatic.
Andreas Backhaus compared cases by age between South Korea and Italy and found a spike in the number of diagnosed people in South Korea aged 20-29.
He says this is due to Italy only testing symptomatic people, whereas South Korea tests everyone and picks up more mild cases.
His data shows that 29.9 percent of all cases in South Korea are people in their 20s. The age group with the second-highest number of cases in South Korea are those aged 50-59, who account for 18.9 percent of all cases.
The data for Italy shows there are more diagnosed cases as people get older. The age group with the highest number is 70-79-year-olds who make up 22.2 percent of all cases.
"Italy has predominantly been testing people with symptoms of a coronavirus infection, while South Korea has been testing basically everyone since the outbreak had become apparent," Backhaus says.
"Consequently, South Korea has detected more asymptomatic, but positive cases of coronavirus than Italy, in particular among young people."
The graph suggests that although younger people may feel fine they are in fact contagious.
"The surprisingly high number of tourists that have been diagnosed with coronavirus after returning from trips to Northern Italy suggests that the unnoticed and asymptomatic spread of the virus has probably been going on there for quite some time, building up to then ravage the elderly," Backhaus says.
He says COVID-19 hit the two countries "very differently" in terms of age even though the outbreak reached them both at around the same time.
He believes that if the virus spreads mainly among young people, then there is no risk to hospitals becoming overwhelmed with patients. But if it spreads to the older population, a hospital collapse "is looming".
Backhaus' post was shared widely online and one Twitter user called it "absolutely terrifying" that young people could be unknowingly spreading the disease.
"The takeaway is not that young people are more likely to be carriers; it's also not sufficient to say South Korea's distribution is an outlier because of its initial outbreak, and leave it that," they wrote.
"It's that while every other country is showing primarily older populations infected because those are who develop more severe symptoms and self-select for tests, we can't ignore that young people contract that virus too."
South Korea has a mortality rate of 0.77 percent from a total of 7755 COVID-19 cases through to March 11. This number is far lower than the death rate in other countries, but it could be due to their thorough testing policies where more milder cases are picked up, Business Insider says.
Italy has the highest mortality rate in the world where 4.25 percent of people who had COVID-19 have died.
Globally, there have been a total of 153,517 confirmed cases and 5735 deaths.