Weekly bulletin was published after a gap of over three months
Photo: iStock The latest ‘weekly’ bulletin by the Indian SARS-CoV-2 Consortium on Genomics (INSACOG) published after a gap of three months noted that the Omicron sub-variant XBB established its dominance in India in November and now accounts for 63.2 per cent of all sequenced cases.
A descendent of XBB is currently making headlines in the United States and some other countries for being more immune-evasive than its predecessors.
On January 3, 2022, INSACOG, a consortium of 54 genome sequencing labs, published three bulletins back-dated to November 28 and December 5 and 12, 2022.
The last weekly bulletin was published on September 12, which revealed the dominance of BA.2 and its descendants, and the exit of BA.5.
The body had issued a statement on XBB recombinant lineage October 28, 2022, assuring “INSACOG is keeping a close watch and monitoring the emergence and evolution of XBB and XBB.1 and any new sub-lineages.”
Month-wise distribution of SARS-CoV-2 variants in India
Source: INSACOG weekly bulletin, December 12
The bulletins published now come on the heels of the Union health ministry writing to state governments on December 20 to ramp up sequencing efforts after the tsunami of cases in China, the US, Korea, Brazil and Japan.
XBB was dominant in India until November and began to be replaced by BA.2.75 by early December, the INSACOG dashboard showed.
Region-wise graphs revealed a similar trend for northern, western and eastern states, where XBB first emerged around the 35-38th week of 2022 and slowly established its dominance by the 43rd week but started getting replaced by BA.2.75 around the 45-46th week of 2022.
Vinod Scaria, a scientist at the Council of Scientific and Industrial Research Institute of Genomic and Integrative Biology (IGIB), argued in his Twitter analysis that this seems improbable, citing multiple explanations. These included geographical sampling bias, small (number) of sequences, additional mutations in BA.2.75 that could provide advantage over XBB or a new variant (which has been) misclassified.
In the northeastern states, XBB was only detected in the 41st week of 2022 and vanished completely thereafter. BA.2.10 was dominant in the 42nd week, BA.2.75 in the 46th week and no data in between this time period. In complete contrast, XBB continued to be the most circulating variant in southern and central states.
INSACOG, formed in December 2020 to strengthen genome sequencing efforts in the country with just 10 labs at the time, has been repeatedly accused of not sharing information on a regular basis.
Most recently in April 2022, it shared sequenced data after a similar gap of three months, Down To Earth had reported earlier.
There was almost a month-long gap in the publishing of the weekly bulletin between July and August 2022. So far, some 303,908 samples have been sequenced in India.
Since April 2022, India had sequenced just 0.397 per cent of its total cases, according to data available on the Global Initiative on Sharing Avian Influenza Data, the world’s largest database of novel coronavirus genome sequences.
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