Cruises a 'perfect test' to see if we are ready for phase 3: experts
But polymerase chain reaction (PCR) tests remain highly accurate, experts add
Polymerase chain reaction (PCR) tests are highly accurate, but may not detect a coronavirus infection still in the incubation phase.
The incubation period, which is the time between exposure to the virus and symptom onset averages about five days, but can be up to 14 days, experts said.
While MOH said last night that the man who had tested positive on board the Quantum of the Seas cruise ship - he had cleared the test before departure - had subsequently tested negative, infectious diseases physician Ling Li Min told The New Paper that positive tests on cruises can be expected.
"Way back when we were testing teachers and stallholders, some tested positive even though they were all asymptomatic," she said.
"So when it comes to the cruises, we can expect to see more cases that were previously undetected."
She explained, however, that such cases are likely to be past infections, with those found positive carrying the dead virus.
"The test will detect the virus, but can't tell if it's dead or alive," she said.
Before MOH reported last night of the two negative tests of the cruise passenger, Trade and Industry Minister Chan Chun Sing had said resuming economic activities entails some risk.
Necessary contact tracing and isolation protocols have been put in place to manage situations such as these, he added.
Meanwhile, infectious diseases specialist Leong Hoe Nam said cruises to nowhere are a "perfect test" to see if Singapore is ready for phase three.
Dr Leong said the case detected on the Quantum of the Seas would test contact tracing abilities and the reliability of measures such as TraceTogether.
"This cruise line incident is a perfect trial run or test to see if we can get our act together if another new case pops up," he said.
"This cruise will not be our Diamond Princess. Rather, it will be a diamond model for us of how we handle new cases in the future."
The Diamond Princess was a ship operated by Princess Cruises that saw a massive outbreak on board earlier this year, with more than 700 of its 3,700 passengers and crew infected, resulting in 14 deaths.
The ship was quarantined in Japan for nearly a month with its passengers on board.
Dr Leong added that the Quantum of the Seas incident was the new normal, and more cases in the community are to be expected.
"But it is the co-operation of the government and the people that will be the final united front against the virus," he said.