The findings come from scientists from Singapore’s National Centre for Infectious Diseases and the Academy of Medicine.
The research finds that person infected with COVID-19 becomes contagious around two days before symptoms show.
The study then holds that the patients then remain contagious for between seven and ten days after they start showing signs of the disease.
This includes having a high temperature and a new and continuous cough.
Researchers said COVID-19 “could not be isolated or cultured after day 11 of the illness.
Positive tests in patients that still had symptoms after two weeks could be picking up sections of the bug that cannot pass the virus on to someone else.
The study examined 73 patients infected with COVID-19.
The authors wrote: “Based on the accumulated data since the start of the COVID-19 pandemic, the infectious period of [coronavirus] in symptomatic individuals may begin around two days before the onset of symptoms, and persists for about seven to ten days after the onset of symptoms.
“Active viral replication drops quickly after the first week, and viable virus was not found after the second week of illness.”
Recently, 18 patients who had mild symptoms were released after spending between 38 and 51 days in a care facility, despite continuing to test positive.
Singapore’s Ministry Of Health said they were shedding “dead viral components”, which, though detectable in testing, were inactive.
They had to quarantine themselves for seven days after their release.
When asked about the new study, the MOH said it “will closely study the position statement and evaluate how we can incorporate the latest evidence… into our patient clinical management plan”.
The research confirms a previous study in Germany, that similarly holds that COVID-19 patients stop shedding the virus by day 8 of infection.
When asked why it took three days longer in Singapore, Prof Leo said the researchers here were “very conservative and counted till the very last drop”.
The only exceptions to this are patients with weakened immune systems, such as cancer patients receiving chemotherapy or people on immunosuppressant drugs following a transplant.
The virus in them might remain viable for a longer period.