E-Paper
Amid concern, expert panel Insacog says XBB variant mild
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.
Indian patients found positive with Omicron sub-lineage XBB of Covid-19 have reported mild illness and no increase in severity, an expert panel said on Monday on the current sub-lineage detected in multiple states.
“XBB, a BJ.1/BM.1.1.1 recombinant lineage with breakpoint in the spike protein is presently appearing in multiple countries. This recombinant lineage was first detected in Singapore and US and has also been identified in multiple states in India. A sub-lineage of XBB with an additional mutation is also detected (XBB.1),” INSACOG said in a statement.
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.
“Modest increase in the spread of XBB in Singapore has been observed. However, there has been no report of increase in severity of disease or increase in hospitalization associated with these variants. Among the Indian patients, the disease is mild like with other Omicron sub-lineages, and no increase in severity is noted,” it noted.
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The sub-lineage spread at a greater speed in Singapore, taking over the earlier dominant sub-variant BA.5. Till mid-October, XBB accounted for at least 60% of all new cases in the island nation.
The sub-lineage is spreading rapidly in India, with nearly 50% of the samples sequenced in the past couple of weeks reporting positive for it, according to people familiar with the matter.
Quoting data from INSACOG dashboard, Vinod Scaria, scientist at the Institute of Genomics and Integrative Biology, tweeted: “Data suggests XBB* has emerged as the predominant lineage of #SARSCoV2 in #India in the recent weeks. XBB* now accounts for ~48% of all isolates in epiweek. No abnormal spike in infections or clinical outcomes have been noted yet…”
Scaria, however, did mention that asymptomatic infection and transmission cannot be discounted, given the background immunity in population.
WHO’s Technical Advisory Group on SARS-CoV-2 Virus Evolution (TAG-VE) met on October 24 to discuss the latest evidence on the Omicron variant of concern, and how its evolution is unfolding. The overall phenotype of XBB does not diverge sufficiently from other Omicron lineages with additional immune escape mutations, in terms of the necessary public health response, to warrant the designation of new variants of concern and assignment of a new label, it said.
“The TAG-VE discussed the available data on the growth advantage of this sub-lineage, and some early evidence on clinical severity and reinfection risk from Singapore and India, as well as inputs from other countries. There has been a broad increase in prevalence of XBB in regional genomic surveillance, but it has not yet been consistently associated with an increase in new infections. While further studies are needed, the current data do not suggest there are substantial differences in disease severity for XBB* infections,” WHO said in a statement.
There is, however, early evidence pointing at a higher reinfection risk, compared to other circulating Omicron sub-lineages.
“Cases of reinfection were primarily limited to those with initial infection in the pre-Omicron period. As of now, there are no data to support escape from recent immune responses induced by other Omicron lineages. Whether the increased immune escape of XBB is sufficient to drive new infection waves appears to depend on the regional immune landscape as affected by the size and timing of previous Omicron waves, as well as the COVID-19 vaccination coverage,” the statement said.
INSACOG is keeping a close watch and monitoring the emergence and evolution of XBB and XBB.1, and any new sub-lineages, it said in the statement, and assured that the public at large need not panic, while recommending adherence to corona appropriate behaviour in the light of ongoing festivities.
While this is the first INSACOG statement issued on XBB, it has come nearly three weeks after the sub-lineage was detected in the country. The bulletins on currently circulating strains were supposed to be a weekly exercise.
Six INSACOG bulletins— from July 18 to September 12— providing details on the new and emerging variants of SARS-CoV-2 in circulation in the country were simultaneously released last week.
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The last bulletin was released on July 11 and the latest one—among the six released— is almost a month old, highlighting the huge gap between the data that the government shares and the reality on the ground in terms of SARS-CoV-2 variants currently in circulation across India, as this RNA virus mutates at a greater rate.
Different government ministries and departments are involved in managing INSACOG. However, according to people familiar with the matter, it is the health ministry that is to give final go ahead on what is made public.
“INSACOG has been releasing bulletin religiously every week as mandated and submitting it to the authorities concerned. There is no delay from the side of laboratories or the consortium,” a member of the consortium said, requesting anonymity.
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.
It is the fear of spreading panic among masses that is making the health ministry hold back on regularly putting out relevant data in public domain, according to people familiar with the matter.
“There were instances in the past when certain portions of the bulletin were controversial, making the health ministry take a decision to vet information before approving it for release in public domain,” said a government official, declining to be named.
Meanwhile, providing the Indian scenario, the INSACOG bulletin informed that BA.2 sub-lineage of the Omicron variant of SARS-CoV-2 was the dominant strain in circulation.
“Omicron and its sub-lineages continue to be the dominant variant in India. BA.2 and its descendent lineages, in particular, BA.2.75 has been mostly found over the last week in different parts of India. The incidence of BA.5 has decreased in the last few weeks. Any surge in hospitalization or any disease severity has not been observed during this time period,” reads the report.
