Prof Partho Sarothi Ray was one of the few scientists in the world who first educated the WHO about the character of Sars-Cov-2 when it hit Wuhan first. His continued research on coronavirus helped the medical community evolve a new strategy to combat the pandemic. Ray spoke to THE WEEK from the US where he is now doing cancer research.
Excerpts
Today, the world is terrified by new strain of coronavirus. What is its character?
Omicron is much more transmissive, but less virulent. Therefore, the disease is much less severe, often asymptomatic. If you remember, in my first interview with you, I had predicted that the virus will get attenuated. This seems to be the attenuated strain of the virus. With this, all my predictions in my first interview with you have come true.
So, it would not require hospitalisation or oxygenation of patients? Omicron is also very evasive so far as vaccination is concerned
Yes, its main evolutionary feature is immune evasion. The S- protein is so mutated that antibodies from none of the existing vaccines recognise it efficiently.
Which vaccine is more effective against mutants, mRNA or Adeno?
The mRNA vaccine seems to be more effective. However, it doesn't reduce rate of infection.
Why? If you could simplify
The vaccine also generates a cellular response, besides raising antibodies. The cellular response is preventing severe disease, although the antibodies are not much effective.
So, why mRNA vaccine does not reduce infection? Due to low cellular response?
No, the cellular response seems to be higher in the mRNA vaccines, so they are protecting better against severe diseases. But in terms of preventing infection, all the vaccines are nearly equally ineffective.
Why are they less effective, due to production of less antibodies?
No. Because the S-protein in the Omicron strain has undergone such changes that the antibodies which are against the S-protein of the original SARS-CoV-2 does not recognise the changed S-protein of the Omicron variant efficiently.
We also saw it in the case of Delta strain which was dangerous. Why Omicron is not deadly compared to Delta?
This is a very interesting aspect of viral evolution. The coronavirus has undergone mutations to evade the immune system, and as a result it has also lost some of its abilities to replicate efficiently in human cells. This is a byproduct of the mutation process. This has made it milder than the Delta variant. This will be an ongoing process and might give rise to even milder strains of the virus (in the future).
So, according to you the days of fear are over?
That is difficult to say. At any moment another variant can arise which can be more dangerous. No one can prevent that. But in general, the virus will get attenuated or weaker in terms of lethality.
That sounds complex. Are you thinking of Africa where people are hardly vaccinated, and more deadly variants might come out there?
Yes, that is the importance of the vaccination. Vaccination will prevent the availability of further hosts to the virus to replicate and mutate. The Omicron is rather a product of vaccine inequality where large populations in poor countries are still not vaccinated and will provide populations for the virus to further replicate and give rise to new variants.
So Africa should be the continent of global concern?
Not only Africa, it can happen in India too.
But India is largely vaccinated
No. Double dose vaccination in India is still just 41.8 per cent. In fact 43 per cent as of today.
How important is booster dose?
I don't think the booster dose is required beyond elderly population and those with comorbidities
So, why for the elderly and not for younger ones?
Because the elderly already have weaker immune system and might require a booster for longer protection. Also, the main reason for mortality due to COVID-19 is old age
Do people with COPD (chronic obstructive pulmonary disease) need booster dose?
Yes, a booster might be useful for people with lung diseases.