Scientists keep getting Covid-19 predictions wrong: Here's why

(From left) ST senior heath correspondent Salma Khalik, Duke-NUS Medical School's Professor Ooi Eng Eong, NCID executive director Leo Yee Sin and Saw Swee Hock School of Public Health's Associate Professor Hsu Li Yang during a Covid-19 webinar on Sep
(From left) ST senior heath correspondent Salma Khalik, Duke-NUS Medical School's Professor Ooi Eng Eong, NCID executive director Leo Yee Sin and Saw Swee Hock School of Public Health's Associate Professor Hsu Li Yang during a Covid-19 webinar on Sept 16, 2021.ST PHOTO: JASON QUAH

SINGAPORE - If scientists have learnt anything about Covid-19 over the past 20 months, it is that they don't know enough.

The disease is so different from anything humanity has ever dealt with that it is important for people to adopt flexible mindsets, and be open to changing course once new data emerges, said National Centre for Infectious Diseases executive director Leo Yee Sin.

"We thought we knew so much about coronaviruses and how they would behave," Professor Leo said, recalling predictions made last year when the virus was brand new. "And we were totally wrong."

She added: "Along the way, things may change. Therefore, we cannot continue to hold on to the preset planning... The virus will evolve and will impact our lives."

Prof Leo was speaking at a webinar on Covid-19, which was organised by The Straits Times on Thursday (Sept 16).

When the pandemic first hit, the Sars-CoV-2 virus was compared to the common cold. But it soon became clear that its impact was far worse - especially among seniors, who often required hospitalisation and even intensive care.

And for months, scientists were unsure if asymptomatic infected individuals could spread the virus to others. This has now been proven possible.

The emergence of the highly contagious Delta variant has also thrown a spanner in the works, given how differently it behaves from its "wild-type" ancestor.

Professor Ooi Eng Eong of Duke-NUS Medical School's Programme in Emerging Infectious Diseases said the virus has - and will continue - to evolve and become better at surviving.

But rarely do such genetic changes take place in isolation, and the many factors involved make it difficult to predict how mutations will occur, he said. In order for the virus to modify part of its genetic material to improve survival, it may have to change other, unexpected portions as well.

Prof Ooi compared it to a key that is attempting to turn a lock - that is, human cells.

Scientists can predict how the virus might modify its "key" so that the lock turns more smoothly.

"But we can't predict the other parts that will change in order for this to change, because it's too complicated," he said. "If anyone tries to predict (what will happen), we're almost always going to be wrong, because our science is just not mature enough to let us do something like that."

The discussion arose after the experts were asked which infection-prevention measures they believed could be eased in the short term, and which may become permanent fixtures.

Their conclusion: Mask-wearing rules are likely to stay, at least for now. But it is difficult to say what else might remain - especially when they have been so often wrong before.

"There are still a lot of unknowns," Prof Leo said. "Whatever we say today... maybe six months down the line, would be completely wrong."