Omicron in India: Is it More Transmissible? Dr Shahid Jameel Decodes
"We may consider reducing the time gap for the 2nd dose of Covishield from the current 16 weeks to maybe 12 weeks."
Two cases of the Omicron variant of the COVID-19 virus have been detected in Karnataka, India. Both cases have a travel history to South Africa. As more details emerge, what do we know about the variant? What do we know about Omicron? Is it more transmissible? Will it cause more severe disease?
For India, should we be looking at boosters for healthcare workers and the elderly?
"India needs to make sure it is getting the vaccines to every eligible citizen as soon as possible, and perhaps should consider reducing the gap in Covishield to at least 12 weeks," says Dr Shahid Jameel.
FIT speaks with Dr Shahid Jameel, a leading virologist and fellow, OCIS at Green Templeton College at Oxford University.
What about these 32 mutations makes Omicron a variant of concern? The WHO said that may possibly lead to an increased risk of reinfections as compared to other VOCs. Could you break it down for us?
Dr Shahid Jameel: Omicron is by far the most mutated variant of the COVID-19 virus that we have seen so far. It has a total of 50 mutations, of which 32 are in a region which we call the spike protein, which is a protein on the surface of the virus. Some of these mutations are within a region which we call the receptor-binding domain. These are regions which are used by the virus to bind to its target cells and to enter cells. This is also the region which is the target of antibodies that neutralize the virus, including monoclonal antibodies that have been used to treat patients. So that is the status at this time.
What we don't know at this time is whether the virus will actually escape vaccine induced or infection induced immunity. That work is going on.
There is some data now available that the virus transmits quite well. So that means that it will continue to infect people.
But whether it continues to infect only those who are susceptible, those who don't have vaccine or infection derived immunity, or whether it also re-infects people who have been previously immunised is not known at this time. What we also don't know at this time is whether it causes more severe disease.
It was seen with Delta and Beta variants that vaccine efficacy fell against these variants. Is this going to be a big concern specially for vaccines that target the spike protein?
Dr Shahid Jameel: Certainly it will remain a concern till you have solid data on it. But I'll take you back to the earlier variant that emerged from that region, which is called the Beta variant. Beta is by far the most immune-escape competent mutant that we know so far. But Beta doesn't spread very quickly. Delta on the other hand, spreads very quickly, but its immune escape is moderate. So the question really is, are these two properties of this virus, immune escape versus transmissibility, are they mutually exclusive?
So it is possible that if this virus spreads very quickly, it may be easily neutralised by existing antibodies? So we don't know the answer to those questions. All this speculation is essentially based on individual sites in the virus that have been mutated and people are speculating based on that.
But a word of caution there is that how individual mutations behave and how a combination of mutations behave cannot really be predicted very easily. So let us wait for the studies but till that time, we need to be very cautious.
There are early reports from doctors in South Africa that those infected have had mild symptoms - soreness and fatigue. Does this indicate the variant will not cause severe disease? Or is it too early to tell?
Dr Shahid Jameel: Yes, absolutely, it is too early. Because there aren't enough patients who have been seen, it is possible that what this doctor saw was only younger patients in whom the disease is naturally mild. So I think let's wait for more results to see whether there are age related differences in the disease severity, if there are population-based differences. But the early signs are at least encouraging that the virus may not be causing severe disease. Having said that, let us not be complacent, let us be concerned, but not get paranoid or get worried too much.
In countries like India, where percentage of double vaccinated is still growing, how concerned should we be?
Dr Shahid Jameel: If I was a policymaker in India, and if I was asked to do just one thing, I would say, I have enough vaccines, let me get the vaccine into as many people as I can over the next one week, two weeks, three weeks, increase the vaccination rate as much as I can. We may also consider reducing the the time taken for the second dose from the current 16 weeks to maybe 12 weeks. Because studies have really shown that 12 weeks onwards, you get better efficacy.
We may also consider reducing the time taken for the second dose of Covishield from the current 16 weeks to maybe 12 weeks. Because studies have really shown that 12 weeks onwards, you get better efficacy.
There are fears of waning immunity among the elderly and the Healthcare Workers who got their vaccines 8-9 months ago. Should we be getting boosters for them?
Dr Shahid Jameel: That's certainly a policy that should be looked at very seriously. Unfortunately, we don't have much data to ask, what is the vaccine effectiveness in these populations? The other issue that we will face in India is that almost 90% of doses given in India are Covishield.
Covishield is not a vaccine that you can use as a booster. If I have had two doses of Covishield, and I get a third dose of Covishield as a booster, it's not going to do very much to enhance my COVID immunity. And that's simply the way the vaccine is, the way the platform is.
So for that we will have to deploy other vaccines. India should look at importing RNA vaccines for healthcare workers. India also has two other protein-based vaccines. One is Novavax vaccine from Serum Institute, the other is a vaccine that Biological E has made, which are both protein vaccines which have gone through trials. The numbers look good, but they haven't been approved yet. So India may consider giving emergency approval to those protein vaccines to be used as boosters in healthcare workers. So those are possibly the policy things that should be looked at carefully.
What about the Zydus Cadila vaccine? Will it work as a booster for Covishield?
Dr Shahid Jameel: Certainly possible. The Zydus Cadila vaccine would also be a good booster. Maybe a small study in healthcare workers initially to show how somebody vaccinated with two doses of Covaxin or Covishield responds to the Zydus Cadila vaccine? Certainly, that's a possibility.
What about Covaxin? Can a third dose of it work as a booster?
Dr Shahid Jameel: Covaxin third dose can be provided. The nature of the vaccine is that while it gives antibodies and helper T cells, it doesn't give what we call killer T cells. And that adds another layer of protection, which unfortunately, all killed vaccines don't give.
Moderna and Pfizer have already said they can update their vaccines to the new variant in 100 days. Can the two vaccines available in India - Covishield and Covaxin, also be updated that quickly?
Dr Shahid Jameel: Not as easily as a DNA or RNA vaccine. So maybe Zydus Cadila should look at tweaking its vaccine. That would be a niche area for that company.
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