South Korea reported on Friday that 91 recovered coronavirus patients have tested positive for the disease again, raising questions over health experts’ understanding of the pandemic.

The prospect of people being re-infected with the virus is of international concern, as many countries are hoping that infected populations will develop sufficient immunity to prevent a resurgence of the pandemic.

The reports have also prompted fears the virus may remain active in patients for much longer than was previously thought.

Korean health officials reported Friday that 91 patients thought to have been cleared of the virus had tested positive again, up from 51 people on Monday.

The Korea Centers for Disease Control and Prevention (KCDC) announced it had sent a team to the city of Daegu, the worst hit area, to investigate why patients there were testing positive again

Some of the patients testing positive again showed no symptoms, while others were suffering from fevers and respiratory issues, according to the Financial Times.

South Korean health officials said it remains unclear what is behind the trend, with the preliminary findings from the investigation in Daegu not expected to be released until next week.

However the KCDC’s director, Jeong Eun-kyeong, raised the possibility that the virus may have been “reactivated” in people, rather than the patients being re-infected.

False test results could also be at fault, other experts said, or remnants of the virus could still be in patients’ systems without being infectious or posing a risk of danger to the host or others.

“There are different interpretations and many variables,” said Jung Ki-suck, professor of pulmonary medicine at Hallym University Sacred Heart Hospital.

“The government needs to come up with responses for each of these variables”.

Source: The Telegraph