The Delta Wave Unmasked

Kuala Lumpur, Sept 15: The Delta variant has seen a spike with its high transmission rate in reported cases across the world. Malaysia is equally not spared from this variant that has clocked an average of 20,000 cases daily over three months. But even so, life goes on and economic sectors are slowly reopening.
Prof Dr James Koh (pictured above), Infectious Disease Consultant and Head, Division of Medicine, School of Medicine at the International Medical University (IMU) sheds some light on the Delta variant during the university’s #NextNormal webinar series.
“It is normal for a virus to mutate,” Koh said, adding that once the virus gains entry into a cell in a body, it releases its genetic material into the cell.
“The cell then uses that genetic material to make more copies of the virus.
“When the virus is replicating rapidly in the community, which happens when there is large-scale transmission, this replication process sometimes makes mistakes. The copies made may not be exact,” he said.
Koh added that as the virus is passed on to more and more people, the higher the chances of it mutating.
Each of the variants has occurred within large outbreaks in different populations such as in the UK, South America and India.
The mutation is a natural process it does not necessarily allow a virus to become stronger or more deadly.
Most times the mutations do not confer any benefits to the virus, but with enough time and opportunity, a mutation can bring an added ability to the virus its survival.

What has changed with the Delta?

The Delta has gained better transmissibility through its mutation. The virus has to first attach itself to the receptors found on the surface of our cells—in the case of COVID-19 it attaches to our respiratory cells.
It does this with its spikes. Once it is attached, it can then gain entry to the cell and the virus can replicate.
With the Delta, the virus has gained modification to its spike protein which allows it to gain faster entry into our cells and therefore replicates faster.
“This is what makes the Delta more transmissible. The protection the vaccines have against the Delta is not as strong as compared to the Alpha, Beta and Gamma variants.
“When the vaccines were produced, they were targeting the original spike protein of the virus and now with the Delta variant the spike protein has changed somewhat,” Koh said.
The current vaccines are still able to stimulate antibodies that can recognise the spike protein in the Delta, although it may not neutralise the virus as effectively as previous variants, he also said.

Droplets vs Aerosols

“It is a misconception that only the Delta variant is airborne. At the beginning of the pandemic, we were basing our knowledge on other similar viruses that were largely spread by droplets.
“As we gained knowledge with research, scientists are now quite confident that the coronavirus is largely spread through aerosol,” he said.
To understand how an airborne virus can spread, he cites an example of spraying insecticide in a room.
“You walk in an hour later and you can still smell it because the particles, as long as the air is not moving, will stay afloat in the air.
“That’s what’s happening with the coronaviruses. If we are carrying the virus and we speak, sing, shout or even breathe quietly in a room where the air is very still, the released viruses will remain in the air,” Koh adds.
According to studies, the virus can linger in still air for between three to nine hours.
“We think that we are exposed to the virus largely from breathing contaminated air that is around us,” Prof Koh said.
Contrary to earlier beliefs, evidence points to the fact that touching contaminated surfaces does not quite contribute to the spread of COVID-19.
This is why today’s SOPs (standard operating procedures) don’t just stop at social distancing, wearing masks, washing hands and wiping surfaces.
The focus should be given to additional measures such as ensuring good airflow and ventilation, as well as encouraging double masking and wearing face shields.
“It’s also safer to be outdoors where the air is free-flowing, rather than indoors where the air is usually recirculated,” he said.
Of course, getting vaccinated is still one of the most important layers of protection.
That said, he reminds us that even if someone is fully vaccinated, there is still a risk of contracting the virus.
“The vaccinated do better in overcoming the infection, but those with comorbidities can still land in the ICU. Living a healthy lifestyle is another important layer of protection.”
“Researchers have shown that even the vaccinated who are exposed to the Delta variant produce the same amount of virus load as unvaccinated people,” he said.
This means that both the vaccinated and unvaccinated are just as infectious when infected.
“The only difference between the two is that vaccinated people don’t stay infectious for as long as an unvaccinated person,” Koh said.
A vaccinated person may be infectious for a couple of days while an unvaccinated person will stay infectious for much longer.

Vaccines and Herd Immunity

The 80 per cent of people who are vaccinated will act as a barrier or protection wall against the infection of people who are unable to get vaccinated, such as those who may have some conditions that do not allow them to be vaccinated.
Malaysia is currently vaccinating people at a very high rate and we are already seeing the fruits of this drive.
In Selangor, for example, where herd immunity has been achieved, cases have dropped drastically.
However, Koh adds that to maintain herd immunity, the community has to be static.
This is why he likes the term ‘localised herd immunity’ to describe the level of vaccination within a closed community.
Once the borders are opened and people start to travel in and out of states or countries then the ratio of vaccinated to unvaccinated will be in flux.
“There will be no way to know if we still have herd immunity,” he says.
He explains that this is the reason we need to look at it globally by getting everybody vaccinated if possible.
“If you are not yet vaccinated, I encourage you to do so. No one is safe until everyone is safe. Only then can we say that the world is a safer place.”
This will be a long-haul ongoing effort, Koh added.
Even as first-round vaccinations are being doled out, booster shots are already becoming a heated topic of discourse.
With the news that antibodies wane after six months from the second shot, countries such as the US, Israel and Singapore are already planning on booster shots for those above 60.
A booster shot will be inevitable as with other viruses and influenza.

Opening Up, Going Out

There are differing opinions about the opening up of shops and businesses to the fully vaccinated but there is the logic behind it.
“People who are vaccinated tend to do better than those who are unvaccinated. In Kuala Lumpur and Selangor for example we have achieved localised herd immunity so you can be out as the borders are still closed.
“Regardless of whether you are vaccinated or not, for now, you need to be mindful of the next person—the person sitting next to you, the person we pass by. Keep sticking to the SOPs until we are all vaccinated,” Koh said.
The opening of schools, earlier being considered in September, has been pushed back, and it’s a step that Koh agrees with as it will allow for the rollout of the vaccination programme for those aged 12 to 18 years.
“So when can we go back to normal? I tell them that this is normal. We will not go back to a pre-pandemic normal.
“We will learn to live with the virus, we will make changes and adapt. We may even one day not have to wear a mask. But the virus itself is not going to go away.” Koh said.

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