As the threat of Omicron’s entry into India looms large, States have increased their genome testing of samples to identify the new variant that has triggered panic across the world.
A clear picture is expected later in the week, say public health experts from across the country.
According to sources, around 3,500 samples are being sent on a daily basis for Covid testing in Gurugram. “And, as per the government guidelines, we also send 5 per cent of the samples of the international passengers on a random basis for genome sequencing,” said the source.
Besides, whether the result is negative or positive, it takes around 4 days to get the complete result of genome sequencing, the source explained.
In other States such as Rajasthan and Gujarat, which have fewer number of positive cases, 100 per cent samples are currently being sent for Whole Genome Sequencing (WSG).
As per the data shared by Gujarat Biotechnology Research Center (GBRC), the genome sequencing lab has so far sequenced a total of 2,932 samples, of which, 1,407 were B.1.617.2 or Delta variant.
“Every month we process 200-250 samples. Most of the samples we have sequenced are of Delta variant so far,” CG Joshi, Director, GBRC, told BusinessLine.
According to a senior Gujarat government health official, the State is sending 100 per cent of its positive samples for WGS on a daily basis. “All those positive samples that have CT-value below 25 are sent for genome sequencing. The results are out in 4-5 days,” said the official.
The Central government’s mandate says minimum five per cent of the positive samples need to be sent for genome sequencing on a daily basis.
The scene down south
Besides Rajasthan and Gujarat, Tamil Nadu has also started doing WSG at the genomic lab, inaugurated recently in Chennai at a cost of ₹2.5 crore. Earlier, the samples were either sent Hyderabad or Bengaluru, and it would take time to get the results. Till Monday night, Tamil Nadu had sent a total of 6,714 samples for WSG, of which, 4,618 were sequenced and 3,964 were found to be of the Delta variant. In other words, 86 per cent of the samples sequenced had Delta variant, said a senior government official.
However, so far, Delta AY4.2 or B.1.1.529 (Omicron) has not been reported in Tamil Nadu, he said.
On Tuesday, the Indian SARS-CoV-2 Genomics Consortium (INSACOG), in its Weekly Bulletin, stated that the total number of samples sequenced by it stood at 99,255 as of November 15.
This is an addition of 2,943 samples over the previous week, ended November 8. Of the total samples sequenced, 29,229, or 29.5 per cent, had the Delta variant, while about 6,852, or 7 per cent, were of AY series.
INSACOG, in its November 15 bulletin, noted that the Delta (B.1.617.2 and AY.x) continues to be the main Variant of Concern (VOC) in India. It also noted that no new VOI or VOC has been noted, as the Omicron threat did not exist till November 24.
(With inputs from Monika Yadav in New Delhi, TE Raja Simhan in Chennai)