(Singapore, Feb 27, 2020) Those Covid-19 patients who have been discharged in the island country won’t have the virus in them but whether these discharged patients can be infected again by the coronavirus is yet to be found out, local experts say.

The comment was made after stories have surfaced in China that one in seven patients who has recovered is still infectious. But the local medical experts say that there is no such issue here.

According to a report from The Straits Times, Professor Leo Yee Sin, executive director of the National Centre for Infectious Diseases (NCID), said doctors monitor virus-shedding in patients’ respiratory tract. Put it in other words, they check if the patient is still releasing live virus and thus remains contagious by taking their nasal or throat swabs.

“Patients are only discharged when they have clinically recovered and molecular testing indicates they have stopped shedding the virus,” she said as quoted by ST.

This means that should they sneeze or cough, there is no virus from them that could contaminate surfaces or infect others.

Among the 93 confirmed COVID-19 cases,  62 have fully recovered from the infection and have been discharged from hospital.

But keeping track of virus-shedding is a precaution Singapore has taken.

Prof Leo said when tests show that patients are completely cured and no longer have the virus in them, they are still kept in the hospital for at least another day waiting for the results of a second test done 24 hours after they have received the first all-clear results.

Beyond that, she added: “Cases who are discharged are reviewed at our clinic.”

According to ST, Dr Li Yueping, director of the intensive care unit at China’s Guangzhou No.8 People’s Hospital, had said that test results of 14 per cent of its patients who had been discharged returned to positive when they went for follow-up checks.

Dr Shawn Vasoo, clinical director of the NCID, said this is not surprising – nor is it worrying.

He said data from the SARS (severe acute respiratory syndrome) outbreak in 2003 found virus in patients’ stool for about four weeks after they had recovered.

But this does not mean the virus is still viable, he said, adding that the coronavirus is spread through droplets.

“As infection is spread by respiratory droplets, if (viable) virus-shedding is absent from respiratory secretions, then these people should not go on to infect others,” Dr Vasoo said.

He added that even if the virus in the stool is still active, it “should not be a source of transmission with modern sanitation and hygiene being observed”.

On whether these discharged patients can be infected again by the coronavirus – as Osaka’s prefectural government said had happened to one of its earlier patients, a female tour bus guide – Dr Vasoo said doctors currently do not know how long patients remain immune to the disease.