The World Health Organization (WHO) said on Saturday that it was looking into South Korea’s report that 91 people who had ostensibly recovered from COVID-19 later tested positive for the virus again.
“We are aware of these reports of individuals who have tested negative for COVID-19 using PCR (polymerase chain reaction) testing and then after some days testing positive again,” a WHO spokesperson told Reuters. “We are closely liaising with our clinical experts and working hard to get more information on those individual cases.”
If two tests taken at least 24 hours apart from each other show negative results, the COVID-19 patient is considered to be “clinically recovered” from the illness, per WHO guidelines.
The organization’s spokesperson said that WHO needs “systematic collection of samples from recovered patients to better understand how long they shed live virus.”
On Friday, Korea Centers for Disease Control and Prevention director Jeong Eun-kyeong said, per Reuters, that the coronavirus may have “reactivated,” not re-infected, in the 91 former COVID-19 patients had tested positive again after they were discharged from isolation.