It is because of a scene in the first season's 10th episode. A doctor talks to one of the lead characters, Yoo Ji-yeon (played by Im Se Mi), about a coronavirus being mutated in order to become a weapon.
My Secret Terrius is currently available on Netflix as part of its Korean drama series library.
The synopsis of this K-drama reads, "A secret agent who detaches himself from the world after a failed operation tries to unravel the mystery behind a neighbor's death."
Here's how the scene goes, based on its English subtitles:
The doctor tells Yoo Ji-yeon: "We must do more research, but it looks like a mutant coronavirus."
Yoo Ji-yeon asks: "Corona? Then MERS?"
The doctor continues: "MERS, SARS, the common flu. They all fall in the same family with the same gene information. The coronavirus attacks the respiratory system. During the 2015 MERS epidemic, the mortality rate was over 20 percent."
Yoo Ji-yeon clarifies: "But that's not serious enough to be used as a weapon. Am I wrong?"
The doctor explains: "Like I said, this is a mutant virus. Someone tweaked it to increase the mortality rate to almost 90 percent."
Looking puzzled, Yoo Ji-yeon says: "90 percent?"
The doctor expounds: "What's more serious is that the coronavirus has an incubation period of two to 14 days. This virus was manipulated to attack the lungs directly within just five minutes of being exposed.
When Yoo Ji-yeon asks if there is a cure, the doctor answers, "There's no cure or vaccine at the moment. They're hard to develop."
A Tagalized version of My Secret Terrius was aired on ABS-CBN from September to November 2019 with the title Codename: Terrius.
The scene was quickly noticed by netizens and posted on social media.
Some netizens believe that the Korean drama series may have predicted the coronavirus:
Others were surprised by this scene that aired two years ago:
But then, there are others who tweeted that My Secret Terrius did not predict the coronavirus, because the term has existed since the 1960s, and refers to a collection of viruses.
British newspaper Metro.co.uk discussed the viral scene, explaining that My Secret Terrius did not predict the coronavirus.
According to the article, the term coronavirus has been used by the medical community for a long time already, and it refers to a number of viruses, including the common cold.
Medicine.net explains that MERS-CoV and SARS-CoV are also examples of coronaviruses.
COVID-19 is a coronavirus that originated in Wuhan, China.
In the story of My Secret Terrius, the coronavirus is depicted to be manmade.
Metro.co.uk points out that while there are conspiracy theories about the novel coronavirus (COVID-19) being manmade, scientists believe that the source of the outbreak is from an animal.