SINGAPORE: Thirteen cases of COVID-19 have been picked up over three months, through a public health surveillance programme that routinely tests samples collected from patients with influenza-like symptoms at general practitioner (GP) clinics and polyclinics.
The sentinel surveillance programme has been ongoing since 2007, said the Ministry of Health (MOH). It tests some patients with symptoms like fever and cough for common respiratory viruses including influenza viruses.
Now, this is being used as one of the ways to monitor the spread of COVID-19 in the community.
This “random testing” in the community complements other COVID-19 screening programmes and “a few cases” have been detected this way, Health Minister Gan Kim Yong had said on Mar 21.
“The idea is to pick up cases that otherwise would not have not been detected,” he said then, adding that this could be because the cases show mild symptoms or they do not fit the criteria to be treated as a COVID-19 suspect case.
READ: Singapore developing nationwide COVID-19 testing strategy to better detect unlinked cases in community: Lawrence Wong
Under the sentinel surveillance programme, about 300 to 600 samples are tested monthly for common respiratory viruses, including influenza viruses, said MOH.
Since Jan 26, three days after Singapore confirmed its first imported case of the virus, these samples were also tested for COVID-19.
Around 1,200 samples have been tested for COVID-19 as of Apr 28, and 13 cases were positive for the coronavirus.
"There is no evidence of widespread community transmission. Contact tracing is carried out for all confirmed cases," said MOH.
OTHER SCREENING PROGRAMMES
Apart from the surveillance programme, there is also active detection of cases by frontline doctors.
According to an MOH circular seen by CNA, suspect case criteria include showing signs and symptoms of pneumonia or severe respiratory infection with breathlessness. Patients who have flu symptoms and have travelled abroad, had close contact with a COVID-19 patient or had stayed in a foreign worker dormitory in the last 14 days are also considered suspect cases.
The polyclinics and more than 200 GP clinics are also testing all patients with prolonged acute respiratory infection to facilitate active case finding of COVID-19 infection in the community.
As of Apr 28, close to 5,800 swabs have been performed on such patients, who have fever of 37.5 degrees Celsius or more, and whose symptoms persist for at least four days. Of these, more than 130 cases tested positive for COVID-19.
Singapore is also testing close contacts of COVID-19 cases found through contact tracing who have symptoms, and any patient with pneumonia.
In addition, the National Centre for Infectious Diseases (NCID) is conducting a study that examines leftover blood samples from people who had their blood taken as part of routine care. They have found no cases of COVID-19 up to the last two weeks of March.
Mr Gan had also said on Mar 21 that cases picked up from surveillance programmes indicate that “there is continued seeding in the community". However the number of new cases in the community has fallen since then.
MOH said on Tuesday (May 5) that the number of new cases in the community has decreased from an average of 17 cases per day in the week before, to an average of 10 per day in the past week. The number of unlinked cases in the community has also decreased to an average of five per day in the past week.
Singapore's current "circuit breaker" measures may be eased when the number of community cases daily fall to zero or single digits over a sustained period of time, Mr Gan said in Parliament on Monday.
MORE THAN 140,000 TESTS DONE
The 7,000 tests done under the sentinel surveillance programme and picked up by frontline doctors are a fraction of the estimated 144,000 tests conducted in Singapore as of Apr 27. Singapore has done about 25,200 swabs per million people, according to MOH’s website.
A large number of these have been conducted in the migrant worker community as the number of cases multiplied among them since last month. MOH has said that the spike in COVID-19 cases is also due to extensive testing at the dormitories. Thousands of tests have been done each day at the dorms, which house more than 300,000 workers.
Of the 20,198 COVID-19 cases reported in Singapore so far, more than 80 per cent are migrant workers residing at dormitories. Of the remaining cases, more than 1,200 are in the general community, about 600 are work permit holders not living in dormitories and more than 550 are imported cases.
About 1,600 are active cases, or patients who remain in hospital, and 1,519 have been discharged as of Tuesday. A large number, or about 16,000 people, are isolated at community facilities as they have mild symptoms or are clinically well. Eighteen people have died so far from complications due to COVID-19 infection.
Going forward, a nationwide COVID-19 testing strategy is being developed as the Government scales up its testing capacity to enable Singapore to open up safely, said Minister for National Development Lawrence Wong in Parliament on Monday.
“It will involve more extensive community surveillance, so that we are better able to detect any unlinked cases in the community,” added Mr Wong, who co-chairs the COVID-19 task force.
The Government will also prioritise the testing of higher-risk and more vulnerable groups, like residents and staff of nursing homes and welfare homes, as well as healthcare workers that have high touch-points with the community. It will then progressively expand testing to the rest of the essential workforce and the broader community.