SINGAPORE - About one in every 1,000 travellers who entered Singapore under the Vaccinated Travel Lane (VTL) scheme has been an imported Covid-19 case in the eight weeks since the scheme started.

In response to queries, the Civil Aviation Authority of Singapore (CAAS) said on Wednesday (Nov 3) that 14 imported Covid-19 cases were detected among 13,731 travellers who entered Singapore between Sept 8 and Nov 1.

The authority said 7,702 of the travellers were short-term visitors or long-term pass holders who are required to apply for a Vaccinated Travel Pass to enter the Republic under the VTL scheme. There were eight Covid-19 cases detected in this group.

There were also 5,353 Singapore citizens and permanent residents who returned through the VTL. Six imported Covid-19 cases were detected in this group.

The remaining 676 VTL travellers were children aged 12 and below. No imported Covid-19 cases were detected in this group.

Residents and children aged 12 and below do not have to apply for a Vaccinated Travel Pass to enter Singapore through the VTL.

The authorities have provided regular updates about the number of short-term visitors or long-term pass holders who have tapped the VTL scheme.

But this is the first time they have disclosed figures about the number of residents and children using the scheme.

Under the VTL scheme, people who are fully vaccinated against Covid-19 enter Singapore without having to serve a stay-home notice. Children aged 12 and below are exempted from the vaccination requirement.

VTL travellers will be required to take a Covid-19 polymerase chain reaction swab test prior to departure for the Republic, and another swab test upon arrival.

It is currently in place for 10 countries, and will be expanded to include Australia, Switzerland and South Korea later this month.

Professor Paul Tambyah, senior consultant at the National University Hospital's Division of Infectious Diseases, said the question of whether an incidence rate of one Covid-19 case per 1,000 vaccinated travellers is acceptable depends on Singapore's risk appetite.

He noted that this would translate into 1,700 imported cases every month, should Singapore return to the levels of visitor arrivals it had in January 2020, before the Covid-19 pandemic rapidly worsened.

"I am not sure if that is considered an acceptable risk level by the multi-ministry task force or the Singapore public," said Prof Tambyah, who is also a Professor of Medicine at the National University of Singapore Yong Loo Lin School of Medicine.

"For me, it is fine as it is probably comparable to imported asymptomatic dengue cases."

He added that based on an analysis of the data on imported Covid-19 cases and the number of visitor arrivals, VTL passengers have about one-eighth the risk of being an imported Covid-19 case compared to a non-VTL passenger.

"I think that a gradual opening up to countries in the various categories with close monitoring would be good... In reality, the proportion of cases which are imported is minuscule compared to the locally acquired cases over the last few weeks," said Prof Tambyah.

Mr Shukor Yusof, an aviation analyst from Endau Analytics, said the data on VTL arrivals indicate that there is a relative reluctance for people to fly on VTL flights into Singapore unless they really need to for work-related or family affairs.

He also said it indicated that only a small number of Singapore citizens and permanent residents are keen to fly and return through the VTL, possibly because of the lack of regional options so far.

Meanwhile, Mr Alan Lim, engagement manager at Alton Aviation Consultancy, said the limited number of travellers on the VTL to Singapore so far is in line with expectations at this stage.

Reasons include caution among travellers, the costs of multiple Covid-19 tests and the fact that eight of the 10 VTLs so far started only on Oct 19.

"Traffic is likely to substantially improve only when both the general and destination-specific restrictions are relaxed, and confidence among the travelling public with the arrangements grow," added Mr Lim.