"South Korea’s New Coronavirus Twist: Recovered Patients Test Positive Again
Doctors believe that the disease may have gone dormant and then come back, posing more challenges for testing
SEOUL—More than 160 South Koreans have tested positive a second time for the coronavirus, a development that suggests the disease may have a longer shelf life than expected.
Many had volunteered for re-examination after exhibiting symptoms such as coughing. Others submitted to extra testing on little more than a hunch despite not showing symptoms. So far, these patients—all of whom needed to twice test negative before leaving medical supervision—haven’t spread the virus to others, local health officials say.
Doctors believe that the disease may have gone dormant and then come back, posing more challenges for testing
SEOUL—More than 160 South Koreans have tested positive a second time for the coronavirus, a development that suggests the disease may have a longer shelf life than expected.
Many had volunteered for re-examination after exhibiting symptoms such as coughing. Others submitted to extra testing on little more than a hunch despite not showing symptoms. So far, these patients—all of whom needed to twice test negative before leaving medical supervision—haven’t spread the virus to others, local health officials say.
"Officials are still investigating the cause of the relapses, but Jeong Eun-kyeong, director of the Korea Centers for Disease Control and Prevention (KCDC), said the virus may have been reactivated, rather than the patients being reinfected.
Other experts said faulty tests may be playing a role, or remnants of the virus may still be in patients' systems.
Reporting from the capital Seoul, Al Jazeera's Rob McBride said the developments were "worrying" for officials worldwide trying to understand the virus.
"Does that mean that there had been a problem in testing? Does it mean that there are many more questions about this virus that the experts simply don’t know? Could it be mutating in some form?" said McBride.
"So there are questions and of course they're questions that are important not only here in South Korea but with epidemiologists the world over, who are in the thick of it as the pandemic advances," he said.
Possible false positives
Archie Clements, professor of infectious disease epidemiology at the Curtin University in Perth, Australia, told Al Jazeera the growing number of those testing positive again in South Korea may simply be because "no diagnostic test is perfect for any disease" and false positives are a fact of testing a large population, especially during the outbreak of a new virus.
Clements also said it is possible the virus is reactivating in the apparently recovered, but noted it was unlikely that those who had previously tested positive and were later cleared had independently picked up the virus a second time.
"I think what is very, very unlikely is that these people are being reinfected by other people," said Clements. "There’s plenty of evidence to suggest that there is quite a strong immune response to infection with coronavirus, and that should protect people from infection for a period of time. What's not currently known is for how long."
https://www.aljazeera.com/news/2020/04/200413110301074.html
Other experts said faulty tests may be playing a role, or remnants of the virus may still be in patients' systems.
Reporting from the capital Seoul, Al Jazeera's Rob McBride said the developments were "worrying" for officials worldwide trying to understand the virus.
"Does that mean that there had been a problem in testing? Does it mean that there are many more questions about this virus that the experts simply don’t know? Could it be mutating in some form?" said McBride.
"So there are questions and of course they're questions that are important not only here in South Korea but with epidemiologists the world over, who are in the thick of it as the pandemic advances," he said.
Possible false positives
Archie Clements, professor of infectious disease epidemiology at the Curtin University in Perth, Australia, told Al Jazeera the growing number of those testing positive again in South Korea may simply be because "no diagnostic test is perfect for any disease" and false positives are a fact of testing a large population, especially during the outbreak of a new virus.
Clements also said it is possible the virus is reactivating in the apparently recovered, but noted it was unlikely that those who had previously tested positive and were later cleared had independently picked up the virus a second time.
"I think what is very, very unlikely is that these people are being reinfected by other people," said Clements. "There’s plenty of evidence to suggest that there is quite a strong immune response to infection with coronavirus, and that should protect people from infection for a period of time. What's not currently known is for how long."
https://www.aljazeera.com/news/2020/04/200413110301074.html
