There were reports earlier this month of over 160 people in South Korea who had recovered from the coronavirus testing positive for the disease again. Similar cases were reported from China, Macau, Taiwan, Vietnam and other places—all places where the coronavirus spread at the start of this year. The South China Morning Post reported some people in China who recovered from coronavirus had tested positive over 70 days after they were discharged from hospital.
At that time, Jeong Eun-kyeong, director of the Korea Centers for Disease Control and Prevention (KCDC), said that the virus may have been “reactivated” rather than the patients becoming re-infected.
Giving credence to this theory are the disturbing findings of a Chinese study, reported by the South China Morning Post on Thursday. The South China Morning Post reported that Chinese researchers had found that coronavirus patients who had recovered and were discharged from hospital could "still carry the virus deep in their lungs," which cannot be detected by conventional testing methods.
The research team, headed by Dr Bian Xiuwu of the Army Medical University in Chongqing, southwest China, based its findings on the postmortem of a 78-year-old woman who had recovered from the coronavirus and had tested negative three times. The 78-year-old woman tested positive for coronavirus soon after she was admitted to a hospital in Chongqing on January 27. She was discharged on February 13, having tested negative for coronavirus thrice in swab tests. However, she died a day later of cardiac arrest.
The South China Morning Post reported, "The postmortem of the woman found no trace of the coronavirus in her liver, heart, intestine, skin or bone marrow. However, the researchers found complete strains of the virus in tissue deep in her lungs. They put tissue samples under an electron microscope to confirm the existence of the intact coronavirus enveloped in a crown-like shell."
The researchers noted the hidden strains had not been causing any obvious symptoms. Current mass testing samples do not use samples from deep inside the lungs. Bian's team argued, "there is an urgent need to understand the pathogenesis of Sars-CoV-2 infection".
The team suggested, "flushing the lungs of patients before they are discharged from hospital, for more accurate detection of hidden strains". This involves the insertion of washing fluid via tube into the lungs through the mouth.
However, doctors quoted by South China Morning Post were sceptical about the practicality of such a flushing method, arguing patients would suffer much.