askST: Will high Covid-19 vaccination rates remove the need for contact tracing and testing?

People waiting in the observation area at the Covid-19 vaccination centre at Marsiling Community Club after receiving their jabs on June 1, 2021. ST PHOTO: NG SOR LUAN

SINGAPORE - As Singapore plans for the new normal with Covid-19 as an endemic disease, top experts spoke to The Straits Times' science correspondent Audrey Tan who moderated a panel discussion on Tuesday (June 1) on Living With Covid-19: Singapore's New Normal.

Here are some questions answered:

On Singapore's response thus far

Q: Has Singapore done enough?

A: Compared with the rest of the world, Singapore has been a lot more cautious, Professor Teo Yik Ying, dean of the National University of Singapore's Saw Swee Hock School of Public Health, said.

In May, when Singapore was tightening responses due to another wave of community outbreaks here, other countries such as Britain and the United States were actually starting to lift many of their restrictions even though on a per capita basis - which is the number of cases compared with the population size of each country - Singapore's outbreak was actually 10 times less than Britain and the US.

"So I don't think it is really a situation of Singapore being too relaxed," Prof Teo said.

"But if you start to think about what could we have done better or if we made a mistake, I think it's important to remember that what has really changed is the coronavirus that we're dealing with right now that seems to have penetrated a lot of our defences."

For instance, the new B1617 variant is far more transmissible and infected people now have a much higher viral load. The incubation period now is also a lot more variable compared with the past, causing infections to slip past the nation's defences.

"So our defence layers now do need to be changed to cope with the changing dynamics of these new variants that are emerging."

Q: Is there a checklist of requirements before a country tightens its measures further?

A: Most countries will avoid a lockdown if possible because lockdowns are economically very damaging. In Singapore's current phase of "circuit breaker lite", these economic effects have already been seen in sectors like food and beverage (F&B), Prof Teo said.

But a lockdown becomes necessary when the situation within the community seems to be spiralling out of control very rapidly, to the point that the country's hospital resources start to get overwhelmed.

"Because that's when people actually start to die from preventable conditions such as Covid-19. And that is when you need to tap on the brakes... so we can allow our healthcare system to breathe and to recuperate," Prof Teo said.

Singapore has avoided a complete lockdown, instead entering sectoral lockdowns while ring-fencing affected areas and doing extensive testing there.

Certain malls have been impacted, such as Jem and Westgate, and these malls were locked down for a period of time for disinfection and to allow chains of transmission to be broken in those places.

"This is a way to allow the rest of society to continue without incurring economic damage. But otherwise, I would imagine every country would try to avoid a total lockdown, particularly when we talk about locking down schools as well because locking down schools has a long-term impact for an entire generation," Prof Teo said.

On vaccines

Q: Will this period of heightened alert affect Singapore's vaccination rates? Will people put off vaccination knowing that there is a possibility of reinfection?

A: There are several dynamics at play, said Dr Danny Soon, chief executive officer of the Consortium for Clinical Research and Innovation.

There is certainly a concern that if there were no cases in the country, people may not feel as motivated to get vaccinated, so the uptick in cases has been a good reality check that the pandemic is far from over.

On whether vaccinated people can still get infected - the data is that vaccinations do reduce the opportunity to get infected. However, it does not completely remove it. But vaccinations are very effective in reducing the severity of the disease, Dr Soon added.

"Very few people who are vaccinated get very ill from the disease, very few people who are vaccinated die from the disease. This is many, many times more in the case of unvaccinated persons."

Given that Singapore now has up to an eight-week wait for the second dose, and optimal protection occurs two weeks after every dose, this allows for a time lag of two to potentially 10 weeks before one is optimally protected by vaccination, Prof Teo added.

He stressed that Singapore cannot wait for an outbreak to happen before people start getting vaccinated.

Q: Will other pillars of Singapore's Covid-19 defence, such as testing and contact tracing, still be crucial if everyone is vaccinated?

A: In the short term, before Singapore has achieved that level of sufficient uptake of vaccines across the whole population, the country will still be relying on expanded testing and contact tracing to keep people safe, Prof Teo said.

"But I do suspect that if our vaccination uptake is able to reach a sufficiently high level, then some of these requirements may be lifted, especially if the same happens worldwide as well."

But given that this is a constantly moving space, much will also depend on the coronavirus, if present vaccines, perhaps with additional booster shots, work well to protect individuals and the community from hospitalisations or any long-term health impact if one is infected, Prof Teo added.

If what is being dealt with is asymptomatic infections or very mild symptomatic infections - where the symptoms are like those of fever, flu or cold, that typically go away within a few days or a week - then there is hope that such protocols can be lifted.

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