Real-world evidence shows what's next in the Covid-19 fight

While good vaccine cover provides light at the end of the Covid-19 tunnel, there are still gaps that we have to mind.
While good vaccine cover provides light at the end of the Covid-19 tunnel, there are still gaps that we have to mind.ST PHOTO: CHONG JUN LIANG

One of the first lessons I was taught at public health school was that "statistics are the numbers that clever people use to tell the story they want to tell".

We were then drilled to scrutinise case definitions, denominators and confidence intervals, before arriving at our own conclusions.

These lessons continue to serve me well after two decades.

Over the past year and a half, we have faced an onslaught of science, facts and numbers that have been interpreted, treated and sometimes twisted, to narrate the Covid-19 story across different parts of the world.

Real-world evidence is not always robust and lacks the rigour of a well-conducted clinical trial.

But examining the right data from the right places provides a lens that allows us to see what the next few months could look like for Singapore.

As at June 28, 3.3 million people, or about 60 per cent of the population, here have received at least one dose of vaccine, and 2.1 million have been fully vaccinated. This means three out of every five people would at least be partially vaccinated and protected against the virus.

The Multi-Ministry Taskforce on Covid-19 has announced that the pace of vaccination would pick up, reaching 80,000 doses - or 1.4 per cent of our population - every day.

At that point, only China would surpass this rate.

It would also put us on track to fully vaccinate two-thirds of our population by National Day.

To appreciate what this would mean for us, we turn to Israel, which like Singapore, has exclusively deployed mRNA vaccines, and which is now close to vaccinating two-thirds of its population.

With progressive vaccine coverage in Israel, there was a corresponding drop in infections.

In older adults, where 90 per cent were vaccinated, the infection rate remained low at about three per 100,000, despite the country coming out of lockdown in March this year.

Yet, a recent resurgence of cases arising from the Delta variant highlights the need to maintain public health measures until herd immunity has been attained.

Minding the gaps

While good vaccine cover provides light at the end of the Covid-19 tunnel, there are still gaps that we have to mind.

In Scotland, which has vaccinated close to 100 per cent of people above the age of 55, there are now large outbreaks in adolescents and young adults who have either declined or who are awaiting their turn to be vaccinated.

It is thus reassuring that almost 80 per cent of Singapore citizens aged 12 to 39 years have signed up for vaccination, which will help us avoid a similar situation.

We will need to maintain existing public health and social measures for a few more weeks, until they are protected.

The other gap would be children under 12 years of age.

Based on current projections by vaccine makers, including Pfizer, Moderna and Novavax, clinical trials for the paediatric population would be completed only by the end of this year or by the first quarter of next year.

Until then, younger children will continue to remain unprotected.

While some concerns have been voiced as to whether children should be vaccinated, particularly with recent fears about vaccine-related side effects affecting the heart, the real-world evidence is again helpful.

In a systematic review published in the British Medical Journal, covering 129 studies worldwide and more than 10,000 children with Covid-19 where over half were hospitalised, it was reported that 22 per cent ended up in intensive care, while 12 per cent required a ventilator. There were 96 deaths.

A separate report by the American Academy of Paediatrics showed that more than four million children had tested positive for Covid-19 in the United States since the start of the pandemic.

A large number were asymptomatic cases picked up from screening, but 1 per cent needed hospitalisation and 335 deaths were reported.

What is clear is that while most children end up with mild disease, this is not always the case.

Had a vaccine been available, it would likely have made a difference for those requiring intensive care or who succumbed to the virus.


Based on current projections by vaccine makers, clinical trials for the paediatric population would be completed only by the end of this year or by the first quarter of next year. Until then, younger children will continue to remain unprotected. PHOTO: AFP

Do vaccines work against variants?

A number of people here have opted for or been inoculated overseas with vaccines of lower efficacy. This creates a potential public health gap as they are not as well protected and may continue to transmit the virus.

To better understand the implications, we look at the situation in three countries: Seychelles, Chile and Mongolia, all of which have achieved among the highest vaccine coverage globally.

All three countries deployed a first-generation inactivated virus vaccine and are now grappling with large community outbreaks caused by variants of concern.

As Singapore opens its borders, we can expect that variants will be introduced and that we will see outbreaks in the pockets which have received less effective vaccines.


As Singapore opens its borders, we can expect that variants will be introduced and that we will see outbreaks in the pockets which have received less effective vaccines. PHOTO: ST FILE

This brings us to the question as to whether current vaccines remain effective against these variants.

Let us look at the United Kingdom, Scotland and Qatar.

While vaccine breakthrough had been reported in these populations, two doses of the Pfizer-BioNTech vaccine were 90 per cent effective against the Alpha variant, and about 80 and 75 per cent effective against the Delta and Beta variants, respectively.

What was important was that vaccination provided almost full protection against serious disease and death for all three variants. At these levels of protection, our current vaccines continue to serve us well.

What can we expect next?

I would like to see vaccine coverage in Singapore go above 80 per cent, and possibly higher in the elderly and those with chronic diseases who are more vulnerable. This will give us a shot in the arm to deal with prevailing variants of the virus.

Safe management measures will progressively be lifted, people with Covid-19 treated at home, and travel opening up with green lanes, travel bubbles and vaccination certificates.

While it is too early to be sure, there may be a need for a booster to enhance the immune response as this weakens over time.

Second-generation vaccines that work against different variants will become available by next year, as would oral and injectable drugs that better eliminate the virus.

Meanwhile, I look forward to National Day and having more reasons to enjoy the fireworks.

  • Professor Benjamin Seet is deputy group CEO (education and research) of the National Healthcare Group and adjunct professor at the Lee Kong Chian School of Medicine. He is a member of the Ministry of Health's expert committee on Covid-19 vaccination.