COVID-19 patients can ‘shed high load of virus’ in first week, irrespective of symptoms: Singapore study

SINGAPORE (CNA) – COVID-19 patients can shed high loads of the novel coronavirus into the air and onto surfaces in their first week of illness, irrespective of their symptoms, according to a recent Singapore study published by the National Centre for Infectious Diseases (NCID).

However, the possibility of a patient infecting others through contaminated surfaces is “negligible” after the second week of illness, said NCID in a media release yesterday.

The study was published in collaboration with Duke-NUS Medical School and DSO National Laboratories on May 29 in the Nature Communications science journal. It also suggested a further possibility that novel coronavirus could be dispersed as an aerosol.

The new research builds on earlier findings released in March, which showed that people with the novel coronavirus extensively contaminate their bedrooms and bathrooms.

In the latest study, researchers sampled negative pressure rooms of 30 patients – three in the intensive care unit (ICU) and the rest in the general ward.

Samples were collected from high-touch surfaces including bed rails, bedside lockers, and electrical switches in all rooms.

Researchers also took samples from surfaces of toilet seats and automatic flush buttons in the general ward rooms.

Results showed that high-touch surface contamination was “significantly higher” in the rooms of patients in their first week of illness.

However the extent of contamination declined as the duration of the illness increased, while no surface contamination was found in any of the three intensive care rooms.

“This could be an indication that patients in ICU shed less virus as they are usually in their second week of illness,” said NCID.