Science 28 Nov 2021 Omicron brings back ...

Omicron brings back pandemic fears

DECCAN CHRONICLE. | SWATI SHARMA
Published Nov 28, 2021, 7:11 pm IST
Updated Nov 29, 2021, 1:21 am IST
Scientists and doctors are on alert as the global fear of another virus surge seems apparent
A representative picture of the Covid 19 variant
 A representative picture of the Covid 19 variant

The World Health Organization (WHO) declared the recently discovered B.1.1.529 strain of COVID-19, first detected in South Africa on 24 November, to be a ‘variant of concern’. The WHO has renamed the variant ‘Omicron’.

The classification puts Omicron into the most-troubling category of COVID-19 variants, along with the globally dominant Delta and its weaker rivals Alpha, Beta and Gamma. In fact, Dr Gagandeep Kang, reputed microbiologist and virologist, has even stated that the new variant could be more transmissible and may escape immunity.

 

With much uncertainty prevalent, this variant has certainly raised concerns across the world. Authorities even fear a wave of infections much worse than what was witnessed during the dreaded Delta wave outbreaks.

Experts from across the country share their views:

Virus can’t sustain for long...
...Says Dr G V Rao, Director & Chief of Gastrointestinal & Minimally Invasive Surgery at AIG Hospitals. From what is known currently, B.1.1.529 has multiple spike protein mutations, and preliminary analysis suggests it is highly infectious. Almost all the cases with the Omicron variant were fully vaccinated individuals but the good part is they didn’t develop any severe symptoms. We need to be cautious and continue our vigilance regarding this new variant. There’s also a silver lining — with such high number of mutations, the virus becomes unstable and can’t sustain in real world for long.

 

Vaccination should remain a priority despite questions about effectiveness against Omicron because it is likely that they still remain protective to a certain extent. Best is to stick to the basics, i.e., keep the mask on, get fully vaccinated, maintain COVID appropriate behaviour. It is also advisable now to advocate for the booster especially for the venerable population.

Dr K Subba Reddy, Sr. Consultant, Critical Care, Apollo Hospital, tells us that investigations are underway to determine the possible impact of these mutations on the capacity of the virus to transmit more efficiently, to impact vaccine effectiveness and evade immune response, and/or to cause more severe or milder disease.

 

‘It’s commonly referred to as super strain by healthcare experts as it has more than 30 mutations, twice as many as delta variants. According to preliminary reports, the 32 mutations in its spike protein make it 40% less vulnerable to the vaccine as compared to the other variants.

l We don’t know if it’s more transmissible than Delta. We have no data on how much more transmissible it is.

It is unknown if it causes severe disease and death.
It is unknown if it can escape vaccine-induced and naturally acquired immunity.

 

It is likely, however, that fully vaccinated individuals will be protected against hospitalisation, severe disease, ICU admission and death. We have yet to encounter a variant that is so-called resistant to vaccines.

It’s a variant of concern, but still early days

Dr Satyajit Rath, leading immunologist from India associated with Indian Institute of Science Education and Research, scientist from National Institute of Immunology, physician and pathologist, shares his thoughts.

‘A fraction of SARS-CoV-2 virus samples from COVID-19 cases are being routinely tested for the full genetic sequence. Different countries do this differently; some like the UK or South Africa do it intensively, while some like India, much less. When a particular set of differences begin to show up together in these genetic sequences, repeatedly and quickly, alarm bells ring. That’s because it indicates a new ‘strain’, or ‘variant’ of the virus. This is how the Omicron variant has been identified, initially in Botswana and South Africa, then in neighbouring countries, and now in Israel, Hong Kong and Belgium as traveller cases.

 

Omicron is somewhat concerning for a number of reasons. First, it’s not a descendant of the Delta variant but a ‘cousin’. Second, a new variant commonly shows only a few differences in its genetic sequence, but the Omicron variant shows a large number. Third, many of these changes are in the sequence coding for the ‘spike’ protein of the virus, which is the target of COVID-19 vaccines, raising the worry that the current vaccines may not protect as well against this variant. Fourth, this variant’s emergence appears to coincide with a sudden spurt in case numbers in South Africa; this indicates, though not proven yet, that it may be much more transmissible than the Delta variant. The first obvious caution is that it is early days as yet, with little definitive information, and we should wait for evidence to emerge. We don’t know if Omicron is ‘really’ as highly transmissible, though it could be, though there’s no reason yet to think it causes severe illness.”

 

Whether vaccines ‘work’ against a virus or strain is not a ‘yes/no’ issue. Vaccine-related reality is a graded matter, and not if it’ll protect completely or not at all. While current vaccines may provide slightly reduced protection against it, they will likely still provide some protection. Another possibility is that an additional dose of current vaccines may be adequate. The least likely though not ‘out-of-question’ possibility thus far is that we might need a new-generation vaccine, which will take some time to develop, test, manufacture and deploy.”

 

Third wave, experts divided
Experts are divided on whether there’s a possibility Omicron will drive a third wave as big as the second one in India. According to Dr Naresh Purohit, Advisor National Immunisation programme, and Dr GV Rao, the new strain may possibly cause the third wave and escalate cases.

However, Dr Subba Reddy also feels that a third wave is unlikely because of vaccinations. “Already, people have gotten infected and have immunity but numbers may increase, mortality will be less.”

Dr Venkat Ramesh, Consultant Infectious Diseases, Apollo Hospitals, says the anecdotal data suggest that it has the propensity for greater transmissibility because it has been sequenced in many cases quite rapidly, displacing even the Delta variant in South Africa, particularly among student communities in Pretoria and Johannesburg.

 

The available epidemiological and clinical evidence so far shows that it is highly infectious and is not clear that this new variant has the capability to escape the antibody present in a vaccinated or naturally recovered person.

Covishield, Covaxin produce immunity through a different antigen

Indian Council of Medical Research (ICMR) scientist Dr Samiran Panda — who’s also the head of the Epidemiology Department at the country’s apex health research institute, has tweeted that Covishield and Covaxin — the vaccines India has deployed for its national programme — might hold out due to the following reason:

 

“mRNA vaccines are directed towards spike protein & receptor interaction, so mRNA vaccines need to be tweaked around this change already observed. But not all vaccines are similar, Covishield & Covaxin produce immunity through a different antigen presentation to our system,” reads Dr S Panda’s tweet.

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