Omicron sub-variant linked to Singapore Covid surge gains ground in India: Official

Updated on Oct 18, 2022 11:03 AM IST

India is sequencing between 2,500 and 3,000 samples in a month and has the capacity of sequencing 10,000. The current seven-day average of cases in the country is around 2,500.

XBB, which is a combination of Omicron’s BA.2.75 and BJ.1 sub-variants, was first detected in Singapore in August, and has been responsible for a sharp surge in Covid-19 cases in the island nation. (REUTERS) PREMIUM
XBB, which is a combination of Omicron’s BA.2.75 and BJ.1 sub-variants, was first detected in Singapore in August, and has been responsible for a sharp surge in Covid-19 cases in the island nation. (REUTERS)

NEW DELHI: A new Omicron sub-variant of Covid-19, dubbed XBB and responsible for a sharp surge in cases in Singapore, is gaining ground in India, with at least 10-15% samples sequenced in the country showing its presence, according to people familiar with the matter.

And while there are no signs in India, yet, of the highly immune evasive BA.5 sub-lineages— BQ.1 and BQ.1.1— that are currently driving cases in the US and Europe, it is only a matter of time before they make an appearance, the people added, asking not to be named.

In the US, CDC said that these two sub-variants together constitute about 10% of the current cases, and in the UK it’s somewhere between 1-2%. From mid-July 2022, positive cases of these sublineages have been reported also from countries including Nigeria, Japan, France, Belgium, Denmark, and Italy.

XBB, which is a combination of Omicron’s BA.2.75 and BJ.1 sub-variants, was first detected in Singapore in August, and has been responsible for a sharp surge in Covid-19 cases in the island nation.

“These are all cousins of Omicron after all; only names change with time because WHO reclassifies the mutants on a regular basis depending on the trend,” a member of INSACOG said. “We will be analysing data retrospectively, and there is a high probability that the other sub-variants that are driving the surge in Western countries currently are already present in India. So far, all mutants were reported under BA.2.75.”

INSACOG, or Indian SARS-CoV-2 Consortium on Genomics, is a grouping of 54 laboratories that monitors genomic variations in Covid-19 in the country.

“It (naming of sub-variants) is based on set algorithms. The moment a new name gets added, the previous strains are accordingly reclassified,” the person cited above added. “That is the reason we may find some of these new mutants already in our system.”

Nearly 11% of samples sequenced are of BA.5 that was first detected in India in May; BQ.1 and BQ.1.1 are its sub-lineages. Most of these samples are from Maharashtra and West Bengal.

In a preprint paper on Imprinted SARS-CoV-2 humoral immunity induces convergent Omicron RBD evolution-- scientists from various Chinese institutes call XBB the most antibody evasive strain tested. XBB seems to be on its way to surpass the immune evasive status of BA.2.75.2, they added.

“A couple of weeks ago BA.2.75.2 was shown to be the most immune evasive variant seen to date and replicated. That’s now been surpassed by XBB, which is predicted here may challenge BA.5 bivalent vaccine protection,” tweeted Eric Topol, physician scientist who has been analysing data related to Sars-Cov-2 extensively.

Overall, BA.2.75 continues to be the dominant variant in India, according to the INSACOG member. The data from the genome sequencing laboratories is analysed as per the field data trends to study the linkages between the genomic variants and epidemiological trends.

According to experts working for the consortium, this helps to understand super spreader events and outbreaks, and strengthen public health interventions across the country to help in breaking the chains of transmission. Linking this data with the Integrated Disease Surveillance Programme data and patient’s symptoms allows a better understanding of the viral infection dynamics, morbidity and mortality trends.

“The percentage of XBB may be rising, but we have not seen any reason to worry in terms of higher hospitalisations or deaths, and the situation is the same in Singapore where there has been an XBB spike; no higher hospitalization or deaths rate. That aside, we need to be vigilant, and we are closely monitoring the trends,” said the INSACOG member.

India is sequencing between 2,500 and 3,000 samples in a month and has the capacity of sequencing 10,000. The current seven-day average of cases in the country is around 2,500.

“There are not enough samples as a majority of tests are done using rapid antigen, which is not used for whole genome sequencing. Samples collected for RT-PCR testing can be used but in that too not all samples are viable. Also, a machine may be able to run 400 samples in one cycle, but if you have not more than, say 50 samples, it becomes very expensive to run the test,” said another member of the consortium.

Doctors confirm what INSACOG analysis says that there is not a rise in hospitalisations of Covid patients.

“This is an RNA virus; therefore it will mutate at a greater rate. What we need to see is if the mutations are virulent enough to cause severe disease needing hospitalisation, or is leading to more deaths. Looking at the clinical impact, we are not seeing increased hospitalisations. Most patients are testing at home and recovering at home. There is no sign so far that there is anything to worry,” said Dr GC Khilnani, former department head, Pulmonology, All India Institute of Medical Sciences, Delhi.

Get Latest India Newsalong with Latest Newsand Top Headlinesfrom India and around the world.

This Republic Day, unlock premium articles at 74% discount

Enjoy Unlimited Digital Access with HT Premium
freemium
SHARE THIS ARTICLE ON
  • ABOUT THE AUTHOR

    Rhythma Kaul works as an assistant editor at Hindustan Times. She covers health and related topics, including ministry of health and family welfare, government of India.

SHARE
Story Saved
OPEN APP
×
Saved Articles
Following
My Reads
My Offers
Sign out
New Delhi 0C
Saturday, February 04, 2023
Start 15 Days Free Trial Subscribe Now
Register Free and get Exciting Deals