How are we going to defeat Omicron?

Yusuf Akhter


Governments have been once again forced to reconsider their strategies to combat Covid-19, as the Omicron variant becomes by far the most common variant to be detected in most countries. Omicron has wreaked havoc around the world since it was reported in South Africa on November 24th, with the first infection detected on November 9th, 2021.

Since then, its infection has been detected in over eighty countries. According to a recent study employing mathematical modelling, the projected deaths are between twenty-five and seventy-five thousand in England only by the end of April 2022. This has now raised concerns, especially since England has so far administered two doses of vaccine to approximately seventy percent of the population and a booster dose to approximately thirty-five percent of the population.

Omicron has more mutations than any other variant ever discovered, with over fifty mutations when compared with the original SARS-Cov-2. Out of these, thirty-two mutations were found only in the spike protein, which is found on the outer surface of the virus, and out of those, ten mutations were found in the receptor-binding domain of the spike protein, which is the most important component of the protein. This part of the spike protein interacts with the receptor found on the surface of human cells to facilitate the virus in entering into the human cells. Therefore, the role of antibodies against this spike protein in the mechanisms of all available vaccines is important. Many of these mutations have previously been discovered in other variants of the virus, but they have never been discovered together in the same variant of the virus. Now, it will be crucial to see how these changes affect the behaviour of the virus and the illnesses it causes.

All SARS-Cov-2 variants, including the globally most prevalent Delta variant, cause serious illness or death, especially in vulnerable elderly people and/or individuals with co-morbidities; therefore, a pragmatic approach is needed. Recent infection dissemination data shows that transmission of the Omicron is at least three times faster than the Delta variant. However, the good news is that, we already know that the spread of infection can be reduced with precautionary measures like use of face masks, physical distancing, avoiding overcrowding, etc. Scientists from Hong Kong have reported that the Omicron reproduces and spreads in human airways at least seventy-times faster than the Delta version, but it causes mild lung pathology.

Besides, wherever the Omicron outbreak is happening, the proportion of people with serious illness who need hospitalization is lower than the previous Delta wave. A large private study by a health insurance company in South Africa reported that the Omicron outbreak showed twenty-nine percent less hospitalization when compared with the first wave of infections.

Similar outcomes are expected from long-term molecular evolution of any of the infectious viruses. While less lethal, the ability of viruses to become more infectious favours the survival of the offspring of the virus in the future. Mutations make the virus more contagious while also making it less lethal, providing a larger pool of human bodies to these virus particles, providing shelter, nutrition, and machinery for their replication and multiplication in the long run. Eventually, this virus, too, will become a regular cohabitant in our bodies, just as we provide shelter to millions of other viruses. 

It is further reported, when serum from the blood of people who have been previously infected or vaccinated is mixed with the Omicron virus in experiments, it has been observed that the antibodies found in the serum are not able to properly bind and neutralize the viral particles. There have also been reports that the Pfizer vaccine loses sixty percent of its efficacy against the Delta variant and about thirty-four percent against the Omicron variant. A booster dose of the vaccine increases its efficacy against the Delta by ninety-five percent and its effectiveness against the Omicron by seventy-five percent. Conclusively according to a study, when compared to Delta, the Omicron can cause about five times more infections in people who have already been infected or vaccinated.

Let’s have a look at the current situation in the country. As of July 2021, the fourth national sero survey estimated that around sixty-eight percent of Indians carry antibodies against SARS-Cov-2. Given that the proportion of vaccination up to then was very low, much of it came from natural infection. Despite an impressive immunization campaign of 1.3 billion doses, so far forty percent of Indians have received two doses, and sixty percent have received one dose, according to data available at MyGov website, when the article was written.

Global data suggests that even people with prior infection with other variants have a minimal ability to fight against the Omicron. There will be a rapid expansion of symptomatic infections in India in the coming weeks, while the number of hospitalizations may remain lower than in previous waves. However, even this small fraction of our large population could be a big number. Therefore, a more pragmatic approach must be taken to keep the hospital capacity ready and ensure optimum medical supplies.

India should also gear up its vaccination so that at least two-doses can be delivered to as many people as possible. Although with the advent of the Omicron, it seems impossible to prevent another wave, a combination of prior infection and vaccination can prevent serious disease in a large proportion of adults, which will ensure reduction of hospitalization and death. Since the detection of Omicron cases in the country began, the Centre has asked states to activate war rooms in response to an increase in Omicron cases.

Recently the government announced its policy on booster vaccination and children vaccination. There are important questions to consider, such as which vaccines should be used. How many doses will be required, and when these should be administered. Apart from Covishield and Covaxin, other two low-cost recombinant protein vaccines are now being manufactured in India, and these will work well as booster doses. First among them is produced by the Serum Institute of India, for the American company Novavax, the Covovax vaccine, which is already approved in Indonesia and is being exported in large quantities. Corbevax-E, another indigenous vaccine, is produced by Hyderabad-based Biologicals-E in collaboration with Baylor College of Medicine in the USA.

Global data suggests that two doses are required for primary disease protection, with a booster dose protecting against the more severe disease. While we await trial vaccination data for booster dose and on children, we should not postpone our logistical preparations for the rapid implementation of the further COVID-19 vaccination programme. We must learn from the outbreak events occurring in other countries around the world and prepare to fight against the Omicron.

[Dr. Yusuf Akhter is a faculty member at Department of Biotechnology, Babasaheb Bhimrao Ambedkar  University, Lucknow. He is an editorial board member of several reputed journals like Scientific Reports (Nature), Frontiers in Genetics, etc. These are author’s opinions.]


*The opinions expressed in this blog are those of the author.