The first few cases of the Omicron Covid-19 variant have, inevitably, been found in India. Why is there so much worry about this particular strain, given that the world has known SARS-CoV-2, the virus that causes Covid-19, for nearly two years now, and that it was always expected that more variants would emerge, some more dangerous and some less so? Why are many countries seeming to respond with panic and what does this say about this mutation of the virus?

What about the efficacy of existing Covid-19 vaccines against the Omicron variant? Stéphane Bancel, chief executive officer of Moderna, has said that he feels existing vaccines will struggle with this new virus. Why is it that vaccine-makers are not confident? What's changed about vaccines' potential to protect against the virus, with Omicron? To get answers, we spoke with Polly Roy, professor of virology at the London School of Hygiene & Tropical Medicine. Roy has in the past provided the first molecular description of a distinct group of viruses known as the orbiviruses. She holds an Officer of the Order of the British Empire for service in virus research, a Fellowship of the Academy of Medical Sciences, UK and the Indian Science Congress General President's Gold medal.

Edited excerpts from the interview:

What do you understand about the new Omicron variant? Why are we so worried about it? Why are some responding to it with shock?

You noted that the [Omicron variant] is already in India. It has already been in different countries for a while, I'm absolutely sure of that, even though we did not find out till fortunately South Africa did, because they sequenced it. So the [variant] was already around and thus it is not as dangerous as people are making it out to be. Take the Delta variant, for instance. When Delta first emerged, everybody thought we are going to have severe disease and many many deaths, and the vaccines will not recognise it, which actually did not happen, which was not true. The vaccines worked.

In the case of Omicron, it's true there are a lot of mutations. There are really severe, drastic changes in the [spike] protein that binds to the receptor. This is because all viruses make mutations. The coronavirus, in fact, makes much fewer mutations than any other virus because it has a proofreading system. Viruses that don't have this system can't [survive]. That's why coronaviruses have a very strong proofreading system. RNA viruses [like the coronavirus] particularly have to be very cautious about how many changes they can make. In this case, even though we have a mutation, it's not in the receptor-binding site area so much. Thus, if they change too much, the virus will not bind [to host cells] and will not survive. So, there is a constraint there and they can't change too much. And the vaccines target that area, so the vaccines will still work against [Omicron] infection. They may not be 100% as far as [infection] is concerned, but will still perturb the infection, even if less so. It's the same with any variant, because the vaccine was made from the original strain, they cannot change too far. I really believe that it's not going to be so much more dangerous than any other circulating variant right now.

If, as you say, there are differences between previous strains of COVID-19 and the Omicron strain, but it's not conceptually so different, then why is the scientific community and why are public health professionals reacting almost with panic?

The virus may be more transmissible but that doesn't mean that it will cause more disease. These are two separate things: transmissibility versus the [virulence of] disease. Disease outcomes could be very similar [to current variants]. We're going to see the same sort of disease as with Alpha or Delta. I don't think there will be any difference.

You're saying that if you look back at earlier Covid-19 variants, including the earliest strains or Delta and Alpha, the disease impact is still roughly the same?

Yes, absolutely. There's no difference really because the outcome of respiratory disease is the same. The question is of the immune system of the person who is infected. If they're not vaccinated, that's a major problem. We have a better scenario right now because many of us are vaccinated. Even with one dose, we're going to have some protection and with two or three doses, far more. So it is not that easy for the virus to just take over. It's just not possible.

If that really happened, that the virus changed tremendously, we would have known before. The [Omicron variant] was already around, even though we did not detect it. It's not that it's suddenly coming from South Africa. That we stopped South Africans from travelling just makes me wonder how people can think that way, because the virus is everywhere. These days, people are travelling everywhere. Today, I heard this variant was isolated in the Netherlands before it was in South Africa. There are Dutch people in South Africa. There is a continuous movement [between the countries], and something [found] in one will go to the other and vice versa. So what is the reason that we think that South Africa started it first? Similarly, we thought Delta came from India. You don't know where it comes from actually. Because we isolated the variant faster, recognised it faster, doesn't mean that it was really here first.

Could you explain a little more about transmissibility? What does it mean today when we say that a Covid-19 variant is more transmissible? Does it mean that, if earlier maintaining a six feet distance between persons was ideal, should it now be 12 feet distance?

No. Of course, this is a respiratory virus, so you have to inhale it [to get infected]. But the main thing is that if you are infected with, say, 10 particles of the virus, you are not going to spread more than one or two particles. But if you are infected with 10 particles and are very susceptible to the disease, and it thus expands 1,000 times more, your viral load becomes very intense. When you sneeze, you are shedding a lot of the virus, so it will easily spread to many people. Trust me that all variants have the same quality, distance-wise. That's no different. The issue is how much virus a person can spread. An immunocompromised, viral person will spread more whenever he sneezes. How to measure the distance that should be maintained? If you can smell somebody smoking somewhere, that's the distance to think about. It's not about one or two metres, or touching people, or washing vegetables. All that has nothing to do with it. Inhaling through the nose is the main thing. That's how the virus goes in.

Since we last spoke, there has been progress in vaccination across the world. In many parts, the proportion of vaccinated people is quite high. In India too, it's rising steadily, though not so much in Africa. That's one reason why people are more concerned. There are people who have not opted for the vaccination or are not able to access vaccines in many parts of the world. What are the implications of not having the entire population fully vaccinated, in general, and in the context of vaccines' efficacy against Omicron?

As I said, even though there are some changes in Omicron, it is not going to escape the entire immune system. The vaccine is still going to be protective. And vaccines are the only way we can really stop the spread of the virus. It's the best way. Of course, you can do physical isolation, masking, etc. These do help. Though I see people with masks covering their mouth, not their nose. The nose is most important to cover. They must understand that.

Second, I think there is vaccine hesitancy. There are so many communities in different countries that believe the vaccine has some kind of contamination, which is rubbish. All Covid-19 vaccines made so far are good vaccines and good to take, if available. I keep on telling everybody, try to make your own vaccine in your country. [Self] manufacturing has to be done, otherwise, it's not possible to protect everyone. But I understand that even where vaccines are available, people don't want to take them. Even among the young, misconceptions are there. That is also very true in India. And I think it's important in India to talk about it, inform people in simple terms, that you may be sick [after taking] the vaccine, but you will be much sicker if you have the virus. No vaccine will be released without careful testing. In any country, these days, there is very strict regulation for vaccines. So any vaccine available in the market which has properly undergone government regulation is a good vaccine. The best ones, to my mind, are messenger RNA vaccines, like the ones from Pfizer and Moderna. They show higher protection. The Sputnik-V [adenovirus] vaccine is also very good and gives strong protection.

If all the existing Covid-19 vaccines are good enough to protect us against this new Omicron variant, then do we really need a new type of vaccine to address this variant, as manufacturers are saying, or do we need booster shots?

Let's take the second question first. Booster shots for any vaccine raise your antibody level. The more antibodies you have, the better chance at protecting yourself from infection. Even against Omicron, which has changed from Alpha and Delta, vaccines will still protect.

Continuously, vaccines have to be made on new strains, like it is done for flu. It's not difficult to make these very quickly. It just takes a few months. With mRNA vaccines particularly, it's very easy to do it, and it's the same with the adenovirus-based vaccines like Oxford/AstraZeneca [branded Covishield in India], or Sputnik-V, or any of the Chinese-made vaccines as well. None of them are difficult to make. All virologists can make these, based on genetic engineering. My laboratory too can make these very easily. The point is that right now these vaccines are available so we should take these while we wait for the others [to come].

Another variant will also come. You can't stop that. There's no way we can stop variants from entering our countries. It's just not feasible or practical because we are a global community. You can take precautions, you can test everybody coming to see whether they have the virus or not, that's fine. But South Africa discovered [Omicron] so they are now banned from [travelling]. Punishing them like that is unfair to them. They're the ones who released the information. They could have just kept it a secret but they shared it openly. And that's how we got to know that this [variant] exists. Some other people in some other country might have had it already, but nobody looked for it.

The scientific community is also saying that we should wait for more data. What would you be looking out for, in terms of the behaviour or characteristics of Omicron?

They want to see how much this virus can be neutralised by the antibodies raised by vaccines. If you know that the vaccines can neutralise it, then it's very good. This is a simple test that is not going to take time. Second, they will look into changes in the particular area of the spike protein that binds to the [host cell] receptor, and see what changes are still tolerable for the virus, and interactions between the virus and receptor-interacting site. Again, it's very easy to do that. Every country can do it because they have bioinformatics systems everywhere, even if not a sequencing system.

What are you studying now? And what's on the horizon, in general, in terms of the fight against Covid-19?

There are a couple of new drugs coming out from Pfizer and Merck. One is stopping the polymerase from working, but it has to be given very early in the infection. The second one is a protease inhibitor. It's good that both targeted a drug specifically for Covid-19.

Second, everyone is trying for better vaccines now, safer and with antibodies sustained for a long time. I believe very strongly the longevity, sustainability of antibodies is very important. You can't continuously give [booster dose] injections again and again.

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