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Recovered virus patients retest positive due to 'inactivated' virus fragments: experts

All News 11:03 April 29, 2020

SEOUL, April 29 (Yonhap) -- South Korean health experts said Wednesday that recovered coronavirus patients may have tested positive again due to virus fragments that have been inactivated.

As of Tuesday, a total of 277 people who recovered from COVID-19 have retested positive here, according to the Korea Centers for Disease Control and Prevention (KCDC).

A team of infectious disease experts said there was no live virus present in such cases, refuting theories like the virus being reactivated or reinfection.

They said that apparent reinfection cases came because fragments of the virus remained in their bodies and showed up in test kits.

A medical worker gestures toward her colleagues as she enters a special ward for coronavirus patients at Keimyung University Daegu Dongsan Hospital in the southeastern city of Daegu on April 17, 2020. (Yonhap)

The country currently uses a reverse transcription polymerase chain reaction (PCR) test for the COVID-19 virus that works by finding the virus's genetic information, or RNA, in a sample taken from a patient.

The experts said this PCR test is so sensitive that it can still pick up parts of the small amount of RNA from a cell even after the person has recovered from COVID-19.

"RNA fragments still can exist in a cell even if the virus is inactivated," they said in a press release. "It is more likely that those who tested positive again picked up virus RNA that has already been inactivated."

They further said it is virtually impossible for the virus to be reactivated unless the COVID-19 virus causes "chronic infections."

The country reported nine more cases of the new coronavirus Wednesday, bringing the nation's total infections to 10,761, the KCDC said. It marked the 11th day in a row that the number of new infections stayed at 15 or below.


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