The discovery of two cases of the Omicron variant of the coronavirus in Bengaluru has sparked concern about what this means for India.
Here’s what we know so far.
What is the Omicron variant?
Omicron, in keeping with the convention established by the World Health Organisation, is named after a Greek letter. This is the fifth “variant of concern” to have been detected since the Covid-19 pandemic began in 2019. A “variant of concern” has ability to either evade the human immune response, has increased virulence or increased transmissibility that could have a global health significance.
On November 9, as Covid-19 infections began steeply rising in South Africa, doctors collected a sample from an infected patient. On November 24, the country informed the World Health Organisation about a new variant, B.1.1.529. On November 11, a second case of the new variant was found in neighbouring Botswana.
By November 26, the World Health Organisation’s Technical Advisory Group on Virus Evolution had named the variant Omicron and labelled it a “variant of concern”.
Mutations in viruses are commonplace as the virus jumps from one host to another. Mutations often help the virus transmit itself more easily from one host to another. The reason this particular variant is causing alarm is because of the large number of mutations it contains. In a technical advisory issued on November 28, the World Health Organisation stated that there are 45-52 amino acid changes in the virus.
Of these, 26-32 mutations are in the spike protein. A spike protein, located on the surface of a virus, latches or binds itself onto a human cell and helps the virus gain entry. Multiple mutations in spike protein help the virus get easier and faster entry into the cell.
Alpha, Beta, Gamma and Delta, the other variants of concern, also have mutations in their spike protein. Some of these mutations are duplicated in Omicron, while some are new and unique to Omicron.
Why has Omicron sparked global concern among scientists?
The World Health Organsiation has warned that Omicron poses a “very high” global risk, indicating that it spreads faster than Delta, which currently accounts for over 99% of Covid-19 cases globally. The scientific community is concerned that Omicron could replace Delta to become the dominant variant.
The organisation added that there is still “substantial uncertainty” about the transmissibility, spread and severity of Omicron and how it could affect the trajectory of the pandemic.
But reports based on the observations of African doctors suggest that Omicron may have the ability to slip past natural and vaccine-induced immunity and may increase the risk of reinfection for people who may already have had Covid-19. Pharmaceutical companies have also suggested that the new variant may have some level of resistance to available lines of treatments such as monoclonal antibody therapy.
“Given mutations that may confer immune escape potential and possibly transmissibility advantage, the likelihood of potential further spread of Omicron at the global level is high,” the World Health Organisation said in its technical brief to its member countries.
Until December 2, the variant had already been reported from over 30 countries, causing more than 375 cases. The silver lining is that most cases are either asymptomatic or have mild symptoms.
Currently, most of these infections are of people with a travel history to the affected countries. But the World Health Organisation expects the trend to change soon as local transmission in affected countries picks up pace. In South Africa, local transmission has already led to the onset of a fourth wave of Covid-19 infections.
What is happening in other countries?
The most growth in Covid-19 cases due to Omicron has been noted in South Africa, which had 687 new cases on November 22 but over 8,500 cases on December 2. Between December 1 and 2, Covid-19 cases doubled in the country.
Between November 26 and December 2, South Africa recorded 214 deaths due to the virus, up from 142 deaths the week before.
South Africa’s National Institute for Communicable Diseases on November 30 stated that Omicron was fast replacing other variants.
While cases of reinfection and breakthrough infections have been noted, the majority of severe cases continue to be amongst the people who are unvaccinated.
South Africa has fully immunised about 25% of its population – aout 1.46 crore people of its 5.93 crore population, Our World in Data statistics show. By comparison, India has fully immunised nearly 33% of its entire population. Among adults, the coverage in India is even better, with nearly 50% fully vaccinated.
Since children are at a lower risk of severe Covid-19 infection, India is yet to begin vaccinating those aged under 18 years. South Africa on the other hand is immunising teenagers aged over 12 years.
In Botswana, another high risk country where Omicron was first detected last month, cases are not rising as fast as in South Africa. As per the World Health Organisation, the country last reported 159 cases on November 29 and 464 on November 22, down from 744 on November 15.
So is Omicron more infectious than previous variants?
Omicron has two times more spike mutations than Delta. India’s Ministry of Health and Family Welfare in a press conference on Thursday said it is possibly “500% more competetively infectious”. Because there are multiple mutations in the spike protein, there is a high likelihood that the variant could escape the immune response generated by antibodies acquired through a vaccine or because of a previous Covid-19 infection.
This seems to be borne out by the rise in cases in South Africa. However, the World Health Organisation has warned that other factors such as crowding and a lack of masking could also have played a role. Studies are underway to assess this.
Does Omicron cause more severe infections?
This is too early to predict but existing data has not indicated a rise in the hospitalisation rate in South Africa. Though that has been a rise in the absolute number of Covid-19 patients in the country due to the Omicron variant, the percentage of those requiring hospitalisation has remained the same.
While there are concerns that the virus may not respond to monoclonal antibody therapy, that is speculative, said Dr Rahul Pandit, a member of the Supreme Court-appointed National Task Force on Covid-19. “...We are still waiting for reports from hospitals,” he said.
The reason doctors and scientists believe the virus could be resistant to monoclonal antibody therapy is because of the multiple mutations in its spike protein. But other treatment options, such as corticosteroids and IL6 Receptor Blockers, are believed to be effective for managing Covid-19 patients severely infected by Omicron.
The World Health Organisation has noted that the early reported infections in South Africa were among university students, and younger people tended to have milder infections. “But understanding the level of severity of the Omicron variant will take days to several weeks,” the organisation said.
Are vaccines less effective against Omicron?
Omicron cases have been reported among people who have been vaccinated, which means the virus was able to break through their immune response. But has not led to severe infections amongst them. Hospitalisation rates have been higher amongst unvaccinated people than vaccinated ones, which means that in some cases vaccine-induced immunity is able to act against the virus and prevent severe infection.
Before Omicron, even the Delta variant had caused breakthrough infections.
Omicron has also reignited debate over booster doses of the vaccine. Data from both Israel and the UK has shown that a booster reduces chances of severe infection of Covid-19. Even the Indian SARS-CoV-2 Genomics Consortium, a multi-agency network that is monitoring genomic variations in the virus, recommended boosters for people over 40.
However, several African nations that are at immediate risk from Omicron spread, need vaccines to immunise their population with both the first and second doses. In such a situation, a third or booster dose in rich countries may deprive these African nations of the vaccines they need.
The World Health Organisation has emphasised that vaccines are the only means to control the Covid-19 pandemic. It has urged countries to increase the pace of vaccination coverage.
What do we know about the first two cases of Omicron found in India?
On December 1, genome sequencing confirmed two Omicron cases in Bangalore. On November 22, a 66-year-old South African man landed in Bengaluru and tested positive the same day. He was asymptomatic. Two days later, his samples were sent for genome sequencing. On November 27, he flew to Dubai after producing a negative RT-PCR report.
The second case involves an Indian doctor. He had no travel history and Bengaluru Municipal Corporation has still not found his index case – the person or source who infected him. On November 22, he tested positive for Covid-19 and was hospitalised two days later. He was discharged on November 27.
Five people who these two men came into contact with have tested positive for Covid-19.
The case of the Indian doctor raises a crucial point, experts say: Omicron may have been circulating in other countries much before it was first reported by South Africa. Since most people infected by Omicron are mildly ill or asymptomatic, the variant may be silently spreading in several places.
India has increased its genomic surveillance and states have been advised to screen international passengers, with RT-PCR test compulsory for those from high risk countries along with a seven-day institutional quarantine. The Union health ministry has asked all states to prepare their hospital infrastructure to accept more Covid-19 patients, stock up on drugs for Covid-19 treatment and complete installation of pressure swing adsorption plants, that can produce oxygen out of atmospheric air, in case a third wave hits.
Why have Covid-19 cases been low in India over the past six months and does Omicron threaten to change that?
Covid-19 cases in India have been falling since after the second wave peaked in May. The country has been recording fewer than 10,000 cases a day since mid-November. There are two factors responsible for the relatively low number of cases, experts say.
First, the last national sero survey, in July ,had indicated that a large proportion of the country’s population, 67%, has already been exposed to the virus. More recently, Delhi in its sixth sero survey in November found that 97% of the population had antibodies against Covid-19. In Mumbai, a sero survey in September found that 86.6% of the population was already exposed to Covid-19.
Such a high level of exposure means that a great many people have antibodies against the virus.
Second, the vaccination rate is fast climbing. India has administered 126 crore doses till December 3, covering nearly half the adult population.
These two factors may offer some protection against a wildfire spread of Omicron. While a large proportions of Indians have some immunity, either natural or vaccine induced, they may still be susceptible to Omicron because of immune-escaping behaviour that the virus has projected.
How the virus spreads in India is difficult to predict unless more evidence on its transmissibility and immune-escaping behaviour, experts say. Already, with the wedding season underway from November until January, being in crowded venues with many unmasked guests may expose more people to the variant.
This reporting was supported by a grant from the Thakur Family Foundation. Thakur Family Foundation has not exercised any editorial control over the contents of this article.
