NEW DELHI: The Centre on Monday insisted that over 16,000 samples from Covid patients were subjected to whole genomic sequencing in July, August to study the genetic variations in the virus, dismissing concerns that the pace of genomic surveillance had slowed down in the country.
The Union Health Ministry said that initially (in December 2020), sequencing of samples by INSACOG -- the network of laboratories for genomic sequencing of Covid virus -- was aimed at detecting the variants of concern among incoming international travellers and also to see whether any person with VOC has entered the country.
However, as many states such as Maharashtra, Punjab and Delhi started showing rising trends in February this year, the sequencing was enhanced in 4 districts of Vidharbha, 10 districts of Maharashtra and around 10 districts of Punjab.
The government also clarified that the number has not been fixed to 300 samples per month or 10 sentinel sites per state and these are the indicative numbers while the states have been provided with the flexibility of identifying more sentinel sites ensuring geographic representation from all parts.
In addition to the sentinel sites, there is the option for the states of sending vaccine break-through, reinfection or other unusual presentation samples for sequencing to INSACOG labs.
The ministry said that the strategy of sentinel surveillance made sure that samples from each state were geographically well represented as the 5% of random sampling strategy resulted in samples from certain districts being over-represented, while some districts remained unrepresented from States.
“With the decrease in positivity, the samples available from the sentinel sites catering to districts with zero or single-digit weekly new cases have also gone down,” it said, pointing out that currently, over 86 districts in the country are having zero weekly new cases.
As for the past one month, the majority of the new cases are from only two states- Kerala and Maharashtra, this is also reflected in the samples sequenced from various states.
For accurate sharing of sample particulars and timely communication of the sequencing, the data is shared via a portal that shows real-time results, said the government and added that 9066 samples were sent through sentinel sites in July while 6969 samples were shared in August.