The Omicron variant carries concerning mutations that may make it more transmissible and allow it to evade immunity, scientists said on Monday, stressing that the one certainty in the uncertainty of the many things unknown is this -- Covid is not a short-term crisis and vaccines are still a critical tool.
As the world and India slides into escalated Covid anxiety and the global scientific community grapples with the emergence of a new strain with multiple mutations, several experts said current Covid vaccines are likely to be effective against Omicron too.
The B.1.1.529 Covid variant, first detected in South Africa last week, was designated by the World Health Organisation as a Variant of Concern (VOC), the health body's top category for worrying coronavirus variants.
Public policy expert Chandrakant Lahariya noted that Omicron has around 50 mutations. Of these, 32 are in spike proteins, which the virus uses to enter the human cells, and 10 are mutations of high relevance.
These include H655Y, N679K and P681H mutations which potentially increase the transmissibility. The mutations R203K and G204R are being considered to be associated with higher infectivity. Similarly, there are deletions at NSP6, which could result in immune escape, Lahariya, also a physician and epidemiologist, told PTI.
Frequently Asked Questions
A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.
There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.
Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.
A mutation means a change in a nucleic acid base or amino acid molecule. Mutations eventually accumulate to generate variants that differ from the original virus more and more.
According to Lahariya, any emergence of variants should be treated as an important starting point and with utmost caution but not with panic or exaggerated knee jerk responses of border closures at the drop of the hat.
Immunologist Satyajit Rath added that the emergence of the new variant suggests that we need to stop treating the Covid pandemic as a short-term crisis that needed short-term measures but has already passed.
We need sustained, long-term policies and investments in public health at all levels.
According to Rath, a scientist with the National Institute of Immunology (NII) in New Delhi, very little is known about this variant, but it carries a lot of mutations and is associated with a spurt of case numbers in Gauteng province in South Africa.
I would guess that it will probably turn out to be very good at spreading, it will likely not cause more severe disease, current vaccines will probably show some reduction in their potency against it but will not be 'ineffective', and current drugs will quite likely work well against it, Rath told PTI.
Upasana Ray, , a senior scientist at Kolkata's CSIR-Indian Institute of Chemical Biology (IICB), agreed.
The most important tool against this variant is to follow COVID-19 appropriate health guidelines and getting vaccinated. Vaccines should provide at least partial protection against progression of the infection to severe COVID, Ray told PTI.
Virologist Gagandeep Kang said India may have a small advantage.
Fortunately for us, we are in a situation where everyone is no longer susceptible because of vaccine and prior infection.
So in India, we may have a small advantage because a lot of our people were infected before they were vaccinated and we know that the combination of vaccination and infection gives you the broadest possible immune response. So we may be a bit lucky," the eminent scientist and professor at Vellore's Christian Medical College told NDTV.
WHO Director General Tedros Adhanom Ghebreyesus, who has said Omicron has a large number of mutations, some of which are concerning, said on Monday that it reflects the threat of prolonged vaccine injustice.
The longer we take to deliver #VaccinEquity, the more we allow the #COVID19 virus to circulate, mutate and become potentially more dangerous.
The Omicron also been identified in Botswana, Belgium, Hong Kong, Israel and the UK so far. Much of the knowledge about these mutations and their overall impact is based on what we know scientifically and epidemiologically from the study of earlier variants, experts said, pointing out the need for more data and studies.
Whether the mutations in a combination would behave similarly or differently is to be seen, Lahariya explained.
In theory, the variant Omicron has raised some concerns and genuine ones. However, to understand the behaviour better, we need real-life data on each of these aspects, he said.
Considering that clinical symptoms occur a few days after infections, there would be a time lag in developing a better understanding and associating mutations with the clinical picture. Irrespective of all that, preparation and readiness are key for all countries, including India.
There are some lessons for India, he stressed.
Even though no Omicron case has been reported from India... even if a case is reported, it might not mean any new intervention but scaling up existing tools. We have 21 months of experience with the pandemic and our interventions should be based upon science and epidemiological understanding,.
The assumptions on transmission are based upon an existing understanding of the mutations, Lahariya said.
The other data point being used is that it took nearly 10 days for Omicron to become the dominant variant and reach 90 per cent of all variants in one province in South Africa while some previous variants took many weeks to become dominant.
This has been used as an indicator of higher transmissibility. However, that data is on a small number of cases, from limited localities and for a short period of time and cannot be taken conclusive, Lahariya said.
The evidence on immune escape is also theoretical that there are mutations in sections of spike proteins which bind to vaccine-induced antibodies and may reduce the effectiveness of vaccines, he added.
Virologist Ray noted that it is not well known yet how transmissible, contagious and immune escapist Omicron is. That information, she said, requires some circulation time of this variant in the population.
Eventually, we might need next-generation vaccines but we must get vaccinated at least with what we have currently instead of waiting for what we don't have, she added.
Scientists across the world have started laboratory studies on neutralising antibodies against this variant and findings would be available in the coming days.
While the need for more neutralising antibodies against the variant or a reduction in vaccine effectiveness is a possibility, as has been with other variants, there is every reason to believe that vaccines are still going to work, Lahariya said.In India, there has been some complacency at all fronts, especially in the COVID appropriate behaviour as well as uptake of first and second shots of vaccines. But time now to shake off the fatigue and complacency and get vaccinated and keep following Covid appropriate behaviour, he said.