The World Health Organization is looking into reports that some coronavirus patients thought to have recovered from the illness are testing positive after previously testing negative.
“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,” the WHO told The Hill in a statement Saturday.
On Friday, South Korea reported 91 patients prepping for discharge after testing negative for the virus at the center of the global pandemic had tested positive again.
This could mean that patients’ coronavirus has been “reactivated” rather than the patient having been reinfected, officials said.
The WHO said it is “closely liaising with our clinical experts and working hard to get more information on those individual cases.
“It is important to make sure that when samples are collected for testing on suspected patients, procedures are followed properly,” the statement continued.
Despite knowing “some patients are PCR positive after they clinically recover,” the organization said it needs the “systematic collection of samples from recovered patients to better understand how long they shed live virus.”
Hospitalized coronavirus patients are allowed to be discharged after twice testing negative for the virus at least 24 hours apart, according to clinical management guidelines put forth by the WHO.
In mild cases, it can take as many as 14 days between the onset of coronavirus symptoms and clinical recovery, current studies have found, the outlet reports.
Some experts, like Dr. Anthony Fauci, say that antibody tests can show whether someone was recently exposed to the potentially deadly illness and possibly provide insight for determining who is immune.
Last week, the Food and Drug Administration approved such a test, which can also help move scientists forward in terms of vaccine development.