Booster dose imperative to protect against Omicron | Sunday Observer

Booster dose imperative to protect against Omicron

19 December, 2021

A Sri Lankan Virologist and Pathologist based in Hong Kong Prof.Malik Peiris said the Covid -19 virus will continue to find ways to evade whatever protection or immunity generated by people but the vacccines will provide much needed protection against severe disease and death.

In an exclusive interview with the Sunday Observer, Prof.Peiris, said,” Even with two doses of the Pfizer BioNTech (comparatively which gives the highest protection), the level of protection against Omicron was markedly reduced - the neutralising antibodies have gone down to undetectable levels. That is why the booster dose is required.”

Q: At this point of time do we have enough data to suggest or confirm that Omicron causes less sever disease?

A: In our recent study we have specifically said that we don’t have complete data to prove it. The indication at this stage is that it is less severe than Delta.

Malik Peiris

Indicating a slight reduction in the severity of the disease does not prove that it is less threatening. We have to wait for the clinical data. Even if severity of the disease with Omicron is less, we have to take into account two factors - one that this is much more transmissible, which is why we are getting more cases within a month than what we had with Delta. More cases in a short time can overwhelm the hospital system. On the other hand the studies so far only hint towards that probability, but do not necessarily prove that Omicron is less severe.

Severity may be reduced but it does not mean that it is zero. In South Africa where the Omicron outbreak was first reported, things are looking promising, even the impact on their ICU centres is not huge. But the South Africa case will not translate into Sri Lanka. In South Africa 70 percent of the people have already been infected, where the population of over 60 is also less.

Q: With the latest study reports indicating Omicron is less severe than earlier predictions, people are increasingly showing reluctance to get the Pfizer booster dose which is being administered freely by the Government countrywide. What is your advice to the people of Sri Lanka on this issue?

A: Our studies have shown with the two doses of the vaccine, even with the Pfizer, after five months the protection against infections were slowly going down while protection against severe disease was being maintained.

Even with two doses of the Pfizer BioNTech (comparatively which gives the highest protection), the level of protection against Omicron was markedly reduced - the neutralising antibodies have gone down to undetectable levels.

That is why the booster dose is required. The data suggest that a booster doze will develop protective antibodies against Omicron. In Sri Lanka, the majority of people have been vaccinated with Sinopharm vaccine. Studies by Prof. Nilleeka and others have shown the levels of antibodies are lower than other vaccines with Sinopharm and it disappears much faster. That means two doses of Sinopharm are probably not going to protect you from Delta or Omicron.

For these reasons, I would encourage, particularly the high risk category - the people who are above 60 years and those with underlying diseases such as hypertenstion and diabetes to get the booster dose.

Q: Do you think the Covid-19 is now on the wane or will there are more dangerous variants coming up in the future?

A: Yes, we will very likely see other variants. I think what we have to do first and foremost, is to protect ourselves with the initial two doses of the vaccines, and the booster doses as soon as they are available.

Over time, there is vaccine immunity and infection immunity, even in Sri Lanka a significant proportion of people have been infected with Covid-19 now. A combined immunity between vaccination and infection will generate higher level of immunity. It gives better protection against severe disease.

When immunity gradually builds up, over the next year or so, irrespective of which variant comes, invariably the population will be better prepared to face the challenges posed by the pandemic.

The virus will continue to find ways to evade whatever protection or immunity we generate but we have the tools. I think we have to use this in a wise way. Vaccine is not a single solution to the Covid-19. It is just part of the solution.

We have to use the other public health measures like social distancing, hand hygiene, using face masks, avoid large gatherings of people and restrict unnecessary travel to reduce the risk of transmission.

Q: Can’t we draw parallels to Covid-19 and Ebola. How was Ebola outbreak controlled?

A: Ebola was a different virus, it is not transmitted by air. It is transmitted basically by body secretions of infected patients. It requires much more close contact. Therefore, it was easier to break the transmission chain. Ebola transmits three or four days after the patients get sick.

But Covid-19 or influenza or these viruses are different. It can be transmitted even before the patient develops symptoms. There are sometimes asymptomatic patients who will not show any symptoms.

The social distancing norms, face masks and hand hygiene etiquette has shown to reduce the risk of transmission.

Q: The WHO is investigating to find where the Covid-19 virus originated. What is the progress of those investigations?

A: Anybody who knows the science of virology, know the viruses come from nature. Two months ago there was a study from Laos, where they found, a closer relative of the Covid-19 virus in bats.

In 2003, it took about ten years to really find a parent of the SAARS 1 virus in bats. It is certain that this virus came from bats.

But whether there was an intermediate animal host like in the SAARS 1 is yet to be revealed.

If Covid-19 directly came from bats or through an intermediate animal host is still unclear. We will continue to have challenges like this in the future.

Q: Do you think such major outbreaks of diseases are mother nature’s solution to population explosion?

A: Mother nature doesn’t think in such terms. Human’s actions actually increase the risk of these disease spill-overs from animals to humans. Mass scale livestock trade, wild animal trade, such actions increase the risk of new viruses being spread very quickly worldwide.

The massive increase in international travel is another cause. These are not bad but at the same time they increase the opportunities for the viruses to spread at a faster rate.

During the SAARS 1 outbreak, a person travelled from China to Hong Kong. He stayed in less than one day in a hotel before he got sick and hospitalised. During that one day he transmitted it to 15 other tourists in the hotel. Then there were outbreaks in Singapore, Canada and Vietnam, and so on. That is how the global outbreak of SAARS started. This would not have been the case 100 years ago.

Epidemics and pandemics are one part of the problem. As you know the environment pollution, climate change poses more serious threats in the long run. As a species we are living in an unsustainable manner.

Q: Will we ever be able to go back to our pre-covid-19 lifestyle and do you think the new normal is going to stay for a long time?

A: Ultimately in the next two or three years, as I said, the vaccines and the infections – for example if you get infected after the vaccine - will hopefully protect people from severe disease.

We should be able to go back to more productive and less stressful lifestyle. I would not use the term the ‘old lifestyle’ because, it was not the ideal lifestyle.


Findings of study

A recent study by researchers from the LKS Faculty of Medicine at the University of Hong Kong including Professor Malik Pieris has found, Transmissibility of the Omicron variant of the Covid-19 virus is higher than the Delta and the original variant, and have the ability to partially escape immunity from vaccines and past infection.

However, research team says the vaccines are still likely to be effective in protecting against death and severe disease. Therefore they renewed calls on high-risk groups, such as the elderly and those with immuno-compromised conditions or other chronic diseases to get booster doses as soon as possible.

According to the research team the Omicron SARS-CoV-2 infects and multiplies 70 times faster than the Delta variant and original SARS-CoV-2 in human bronchus, which may explain why Omicron may transmit faster between humans than previous variants.

The study also shows that the Omicron infection in the lung is significantly lower than the original SARS-CoV-2, which may be an indicator of lower disease severity.