What Is 'Stealth Omicron' That Is Driving China's Biggest Covid Outbreak? Can It Hit India?

With China shutting down major cities entirely amid a sudden spurt in Covid-19 cases, 'Stealth Omicron' has become a viral search trend on Google. China's new Covid-19 caseload Tuesday more than doubled from the previous day as it faces by far its biggest outbreak since the early days of the pandemic. Chinese authorities have tightened anti-virus controls at ports, shut down auto and electronics factories and implemented a “zero tolerance” strategy that aims to keep the virus out of the country. According to experts, this sudden spike in Covid-19 cases is being driven by a sub variant of Covid-19 being dubbed as 'Stealth Omicron'.

What is 'Stealth Omicron'?

A fast-spreading variant known as B.A.2, also dubbed “stealth omicron” is testing China's zero-tolerance strategy, which has previously kept the virus at bay after a deadly initial outbreak in early 2020. The variant is currently under study by researchers at the UK Health and Security Agency (UKHSA) which on Tuesday announced that it is probing the sub-lineage.

The “stealth omicron" variant has been reported to spread faster than the original omicron, which itself spread faster than the original virus and other variants, according to early research. It is to be noted that Omicron drove the third wave of the covid-19 pandemic in several parts of the world including India where it infected large numbers of people but led to relatively low fatalities as opposed to previous variants like Delta.

In a recent study, a Japanese team led by researchers from the University of Tokyo found that similar to BA.1, BA.2 subvariant of Omicron appears to largely escape the immunity induced by COVID-19 vaccines. "Neutralisation experiments show that the vaccine-induced humoral immunity fails to function against BA.2 like BA.1," the authors of the study said.

However, some researchers have found that the BA.2 sub variant might have the ability to cause severe disease.

Where has 'Steal Omicron' been reported?

Most of the new cases were in northeast China's Jilin province, where 2,601 were reported. Smaller outbreaks have broken out around the country, including in the major cities of Beijing, Shanghai and Shenzhen. According to reports, hospitals have already been built in Jilin province control the rise in cases. 

Why is it called 'Stealth Omicron'?

According to reports, the new sub-variant does not display some of the key mutations of Covid-19 virus's spike protein that makes it distinguishable from previous variants in an RT PCR test. Meaning that the difference in its spike protein from the existing Omicron and previous variants may have made it harder to be detected initially. According to evolutionary geneticist and advisor to the Central Virology Laboratory in Israel, the new variant has similarities with the previous Alpha variant which was once a Variant of Concern. W#hile B.A.2 shared 30 mutations with the other lineage of Omicron. it has 28 traits that are completely new and its own.

Will there be a fourth wave in India?

While most countries have already experienced two-three waves of Covid-19 already, the rising cases of 'Stealth Omicron' being reported in China have caused alarm bells across the world. Not just China, cases of Covid-19 have been shooting up in the United States as well where a wastewater network that works on  Covid-19 numbers and data trends, has warned that cases are rising again. It is not yet ascertained what variant is causing the surge in parts of the US.

In India, the reports of the Chinese rise in cases comes nearly two weeks after researchers predicted a peak in the fourth wave of the pandemic in June. According to a modelling study by researchers at the Indian Institute of Technology-Kanpur, the fourth wave of Covid-19 is imminent in India and may start around June 22 and peak from mid-to-late August.

The yet-to-be peer-reviewed study, recently posted on the preprint repository MedRxiv, used a statistical model to make the prediction, finding that the possible new wave will last for four months.

The study led by Sabara Parshad Rajeshbhai, Subhra Sankar Dhar, and Shalabh of IIT Kanpur's Department of Mathematics and Statistics shows that the severity of the fourth wave will depend on the emergence of a possible new coronavirus variant, and vaccination status across the country.

Will the 'stealth omicron' variant have any impact on this assessment? 

The Indian researchers noted that there is always a fair chance that a possible new variant of coronavirus may have an intense impact on the whole analysis.

The impact will depend on the various factors like the variant's infectibility, fatality, etc, they said.

"Apart from this fact, the effect of vaccinations -- first, second or booster dosage may also play a significant role on the possibility of infection, degree of infection and various issues related to the fourth wave," the authors said.

Officials at the World Health Organization recently warned that Omicron may not be the last Covid variant and the next strain could be more contagious.

(With inputs from Agencies)