INFINITE's Sung Kyu received a COVID-19 positive diagnosis on Sunday, June 27, which made him the latest celebrity to be infected with the coronavirus. His agency, Double H tne confirmed on the same day that the singer is in isolation for the highly contagious disease.

The agency released an official statement to let fans know about the singer's condition. In the memo that was published by Allkpop, Double H tne said that INFINITE's Kim Sung Kyu was notified that he has COVID-19 on Sunday morning and it was explained that the star was being swabbed for testing every week because he is appearing on the stage musical titled Gwanghwamun Sonata. 

The testing is a regular routine among the stage play actors since they frequently gather for the shows. It was learned that Sung Kyu's diagnosis was somehow surprising because he already received his COVID-19 vaccination. He was inoculated with Janssen jab on June 10 and tested positive after just two weeks.

Now, in a new update, it was said that local health authorities commented that INFINITE's Sung Kyu's case could be the very first known Janssen "Breakthrough Infection" in South Korea.

Health officials explained that the idol singer's case had been described as a "breakthrough" because he tested positive for COVID-19 two weeks after receiving a full dose of the vaccine.

"If a case is confirmed positive 17 days after being vaccinated with Janssen, it meets the criteria for a breakthrough infection," Koreaboo quoted the head of the epidemiological investigation team at the Central Quarantine Headquarters, Park Young Joon, as saying during a news briefing that was held on Monday, June 28. "It can be viewed as an estimated breakthrough infection case."

Meanwhile, Double H tne assured fans that INIFINTE's Sung Kyu is fine. He is asymptomatic, and he absolutely does not have any symptoms.