About Fifty-one persons in South Korea have reportedly tested positive again for COVID-19 after they had recovered and been discharged from quarantine.
The patients, from the city of Daegu, were said to have been placed in quarantine after being diagnosed with the virus. Days after being released from quarantine they then tested positive.
Xinhua, China’s official state-run press agency, quoted Korea’s Centers for Disease Control and Prevention (KCDC) on Monday, as saying that the virus was likely “reactivated”, rather than patients becoming re-infected.
As a result of this, the KCDC has concluded plans to send a team of investigators to Daegu, the country’s worst hit region, to conduct an epidemiological investigation into the cases.
The development also goes in contradiction with current studies on how the virus works with Paul Hunter, an infectious diseases professor at the University of East Anglia, dismissing the claim.
Hunter told Daily Mail that the explanation lacks any evidence and attributed a second positive result to a previous wrong result that happens in one out of five tests due to unreliability of swab samples.
“I agree that these will not be reinfections but I do not think these will be reactivations. Personally, I think the most likely explanation is that the clearance samples were false negative. It does appear that swabs for the virus are not 100 per cent reliable,” he said.
In his part, Mark Harris, a virology professor at University of Leeds, said that more reinfection calls for concern but ultimately agreed that a reactivation is unlikely due to presence of immunity already built up by the body system towards the virus.
“The reports that patients who tested negative subsequently tested positive again is clearly of concern. It is unlikely that they would have been re-infected having cleared the virus, as they would most likely have mounted an immune response to the virus that would prevent such reinfection,” he said.
“The other possibility therefore is that they did not in fact clear the infection but remained persistently infected.”
Japan had recorded first known case of a person being re-diagnosed with COVID-19 in February. The patient was said to have tested positive on February 26 after a negative result on February 6.
Masaya Yamato, director of Rinku General Medical Center’s infectious diseases center in Japan had rejected the possibility of reinfection in individuals who recovered fully after showing symptoms.
He claimed that individuals who went through full course of the disease would have fully developed antibodies.
“A recovery [of asymptomatic positive patients] doesn’t mean the virus is gone— it is dormant. A patient who contracts the virus needs about 14 days, or longer in some patients like the elderly, to produce the antibodies,” Yamato said.