A team of South Korean infectious disease researchers has concluded there is no evidence that people can be reinfected with the SARS-CoV-2 virus. The researchers, led by Oh Myoung-don, MD, head of Seoul National University Hospital’s division of infectious diseases, believe that reports of patients who have recovered from COVID-19 and subsequently tested positive again for SARS-CoV-2 were not due to reinfection or reactivation but, rather, to testing errors.^{1 2 3 4 5 6}

According to Dr. Oh, the PCR (polymerase chain reaction) tests used to determine the presence of the SARS-CoV-2 virus and help diagnose cases of COVID-19 cannot distinguish between the virus and harmless fragments of the virus.^{1 2 3 4 5 6} Vaccine developer Seol Dai-wu of Chung-Ang University in Seoul, South Korea agrees. “The RT-PCR machine itself cannot distinguish an infectious viral particle versus a non-infectious virus particle, as the test simply detects any viral component,” Seol said.²

As immunologist Beda Stadler, PhD, former director of the University Institute of Immunology at the Insel Hospital in Bern, Switzerland notes, people who recovered from COVID-19 can still test positive for SARS-CoV-2 because…

… the coronavirus test measures only a very tiny tiny piece of the genome of the virus, and if your immune cells have killed the virus, then you have debris, you have rotten pieces of the nucleic acids in your blood and everywhere, and the assay can pick up these rotten pieces and then it look like as if you’re infected. You’re not. You have won the fight, you’re immune. So [the test] cannot discriminate.⁷

In a recent case involving 260 people in South Korea who had been diagnosed with COVID-19 and recovered, tests detected fragments of the SARS-CoV-2 virus weeks after their recoveries. “The tests detected the ribonucleic acid of the dead virus,” Dr. Oh said.^{1 2 3 4 5 6} He added:

PCR testing that amplifies genetics of the virus is used in Korea to test COVID-19, and relapse cases are due to technical limits of the PCR testing. The respiratory epithelial cell has a half-life of up to three months, and RNA virus in the cell can be detected with PCR testing one to two months after the elimination of the cell.^1 3 5 6

The findings by Dr. Oh and his research team have been confirmed by the Korean Centers for Disease Control and Prevention (KCDC). On May 18, 2020, the KCDC announced that it had studied 285 cases of patients who had recovered from SARS-CoV-2 infection and later tested positive again for  the virus. Despite the positive tests, the agency determined that the patients were not contagious because they did not actually have the virus—that the PCR tests has “falsely identified dead viral matter as active COVID-19 infection.”^8 9

The new research from South Korea has led to new protocols in that country for handling cases involving people who recovered from COVID-19, completed a period of isolation and then retested positive for the SARS-CoV-2 virus. Now, in South Korea, there is no longer a requirement for people, who have recovered from COVID-19 and gone through isolation, to test negative for SARS-CoV-2 before going back to work or school.⁹

Tests for SARS-CoV-2 in South Korea Can’t Distinguish Virus from Viral Fragments