Coronavirus pandemic

Covid-19 patients can be discharged after 21 days if well

They must remain in their home or dorm for next 7 days; changes take immediate effect

Local and international scientific evidence has shown that the virus is no longer viable after the second week of illness, even though tests may pick up traces of the virus' genetic material and therefore yield a positive result. ST PHOTO: JASON QUAH
Local and international scientific evidence has shown that the virus is no longer viable after the second week of illness, even though tests may pick up traces of the virus' genetic material and therefore yield a positive result. ST PHOTO: JASON QUAH

Coronavirus patients who are clinically well by the 21st day of their illness will be discharged, as more scientific evidence shows they are no longer infectious.

But as a precaution, these people will have to stay at home or in their dormitories for another seven days, Health Minister Gan Kim Yong said yesterday.

They will be allowed to return to work after day 28.

"This revised approach will allow recovered patients who are well and no longer infectious to return to the community in a timely manner," Mr Gan said at a press conference, adding the change will take immediate effect.

However, this will not apply to patients with weakened immune systems, who may continue to shed viable virus for a prolonged period.

The Ministry of Health (MOH) had previously required patients to test negative twice over 24 hours before they could be discharged, even if they had not been ill for some time.

But local and international scientific evidence has since shown that the virus is no longer viable after the second week of illness, even though tests may pick up traces of the virus' genetic material and therefore yield a positive result.

Patients are not likely to be infectious after day 14, and are not infectious by day 21, MOH said.

Professor Leo Yee Sin, who is executive director of the National Centre for Infectious Diseases, also highlighted three local studies on the subject.

The first study, involving 18 people, showed that virus shedding is highest during the early onset of clinical illness.

Another study showed that seven in 10 patients test negative for the virus by day 21, with more than nine in 10 testing negative by day 33.

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This shows that a very small number of patients continue to test positive for a long time, Prof Leo said.

The final study found that once the viral quantity in a patient's respiratory sample dropped to a certain level, the virus could no longer be cultured. This happens around the 10-or 11-day mark.

"So if we were to take all this scientific information together, we are confident to say that by the time (patients) reach day 11, and by the time they reach two weeks of their clinical illness, we no longer have any viable virus that we can culture from the respiratory sample," Prof Leo said.

The World Health Organisation recommended on Wednesday that it is safe to discharge coronavirus patients 10 days after their symptoms first appear, if they remain symptom-free for at least another three days after that.

Singapore is requiring that patients stay isolated even longer than that, said Associate Professor Kenneth Mak, MOH's director of medical services.

"So it's a really with an abundance of caution that we have put together a protocol that allows us now to safely move away from needing to test every individual before we discharge them," he said.

Other countries have also begun using or recommending similar criteria to discharge Covid-19 patients. They include Estonia, Ireland, the United States and Britain.

These countries have typically discharged patients between seven and 14 days from the onset of their symptoms, MOH said.

South Korea discharges asymptomatic patients from isolation three weeks after they have been diagnosed with the disease.

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A version of this article appeared in the print edition of The Straits Times on May 29, 2020, with the headline Covid-19 patients can be discharged after 21 days if well. Subscribe