SINGAPORE — Of the 438 National University of Singapore (NUS) students swabbed for Covid-19, all the results are negative except for one that is still pending. The university informed its staff members and students about this early on Thursday morning (March 25). 

The affected students, who are residents at the North Tower of UTown Residence at NUS, were swabbed on Tuesday after low levels of Covid-19 viral ribonucleic acid, or RNA, were detected on March 21 from the National Environment Agency’s testing of wastewater sample collected the day before from the 25-storey residence. 

Dr Peck Thian Guan, senior director at the office of safety, health and environment at NUS, said in the circular that there is evidence to suggest that the detection of the RNA may be due to viral shedding from a recovered past infection among the residents. 

He added that further investigations are being carried out by the Ministry of Health. 

The Wastewater Surveillance Programme (WSP) has been implemented at the university since Dec 7 last year, Dr Peck said.

It is a “safe, effective and non-intrusive way to detect Covid-19 positive cases, in addition to the prevailing safe management measures already in place across our campuses”, he added. 

“WSP is an accurate and sensitive technique to pick up traces of Covid-19, and it will continue to complement all the measures we are doing to ensure a safe campus.”