CORONAVIRUS patients in China are testing positive again for the disease 70 days after being given the all clear.
Doctors on the frontline of the battle against Covid-19 been left baffled by a growing number of cases of people who recover and show no symptoms but test positive.
Medics in Wuhan, where the coronavirus pandemic originated, say it is one of their biggest challenges as the country moves into a new phase of its containment battle.
Currently, the globally recommended isolation period after exposure is 14 days.
Yuan Yufeng, a vice president at Zhongnan Hospital in Wuhan said he was aware of a case in which a patient had positive retests after first being diagnosed with the virus about 70 days earlier.
“We did not see anything like this during SARS,” he told Reuters, referring to the 2003 Severe Acute Respiratory Syndrome outbreak that infected 8,098 people globally, mostly in China.
Yuan said that even if patients develop antibodies, it did not guarantee they would become virus-free.
Some patients had high levels of antibodies, and still tested positive to nucleic acid tests.
“It means that the two sides are still fighting,” he said.
Guo Yanhong, a National Health Commission official, added: “The new coronavirus is a new type of virus.
“For this disease, the unknowns are still greater than the knowns.”
Patients in China are discharged after two negative nucleic acid tests, taken at least 24 hours apart, and if they no longer show symptoms.
The prospect of people remaining positive for the virus, and therefore potentially infectious, is of international concern, as many countries seek to end lockdowns and resume economic activity.
Jeong Eun-kyeong, director of the Korea Centers for Disease Control and Prevention, has said the virus may have been “reactivated” in patients after they were thought to be clear.
In Italy, the first European country ravaged by the pandemic, health officials noticed that coronavirus patients could test positive for the virus for about a month.
The World Health Organisation officials has said it is investigating cases of patients testing positive again.
“We are 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.
“As Covid-19 is a new disease, we need more epidemiological data to draw any conclusions.”