SINGAPORE (May 28): Patients with Covid-19 who are assessed to be clinically well and no longer infections by Day 21 of their illness will be discharged without having to undergo further tests, Health Minister Gan Kim Yong said on Thursday.

As an added precaution, these patients must stay home or at the their dormitories for an additional seven days till Day 28. After this, they will be allowed to return to work, he added.

“This revised approach will allow patients who are well and not infectious to return to the community, said Gan at a press conference by the Covid-19 multi-ministry taskforce.

These changes to the discharge criteria for patients with Covid-19 will take immediate effect. Prior to this, patients needed two negative swab tests within a span of 24 hours to be discharged, regardless if they had not been sick for some time.

However, a recent study shows that while patients may continue to test positive, the virus is no longer viable after 11 days from the person falling ill. After such time, it also cannot be spread to others.

These findings were published by the National Centre for Infectious Diseases (NCID) and the Academy of Medicine’s Chapter of Infectious Disease Physicians.

To further explain the latest move, Gan draws reference to the World Health Organization’s (WHO) recommendation on Wednesday to shift from a transmission-based discharge to time-based discharge for patients who are clinically well.

Under WHO’s guidelines “patients who are clinically well can now be discharged from after 10 days from the onset of illness, plus at least three days without respiratory symptoms or fever,” Gan pointed out.

“As we know more about COVID-19, as a result of both global research, as well as research done locally, we will adjust our medical plan for COVID-19 patients."

NCID executive director Professor Leo Yee Sin, who was also at the press conference, went on to outline three other studies on Covid-19 conducted in Singapore. 

The first study involving 218 patients with the coronavirus showed that virus shedding – which occurs when the virus is transmitted from an infected person to another – is the highest during the early days.

Another study which followed 766 patients found that 30% cleared the polymerase chain reaction (PCR) test by Day 15 of infection. This number rose to 68% by Day 21, before touching a 95% clearance rate by Day 33.

The final study touched on at the briefing highlighted that the virus can no longer be cultured from a sample, once the viral quantity reduces to a certain level.

With this evidence, Associate Professor Kenneth Mak, who is the Health Ministry’s Director for Medical Services, says Singapore’s decision to isolate patients with Covid-19 for 21 days, serves as extra precaution.

"It is already with an abundance of caution that we have put together our protocol. We want to take the precaution for individuals who have conditions that suppress their immune system,” he stressed.