New Delhi, Sep 6: The Centre said on Monday that over 16,000 COVID-19 samples by sentinel sites were sent in July and August for Whole Genome Sequencing (WGS) to check for variants of SARS-COV-2.
The Union Health Ministry said there have been some media reports alleging that genome sequencing and analysis of COVID-19 declined sharply in India even as cases of the disease continued to rise.
Since July onwards, for accurate sharing of sample particulars and timely communication of WGS results, data for samples for WGS by sentinel sites is being shared through Integrated Health Information Platform (IHIP) portal, it said.
This ensures real-time sharing of sample particulars and WGS results. Accordingly, 9,066 samples were sent through sentinel sites in July and 6,969 samples were shared in August, the ministry said.
Genomic surveillance of SARS-COV-2 is crucial to determine incidence and prevalence of the variants of concern.
“It is clarified that the number of sequences, as quoted in the report, seems to be taken from Indian COVID19 Genome Surveillance portal (http://clingen.igib.res.in/covid19genomes/ ),” the ministry said.
“The sequences analysed in the IGIB SFTP are as per the collection date of samples and does not depict the number of samples sequenced in a particular month. The samples sequenced by labs of INSACOG consortium also depends on the samples sent by the respective states,” the ministry said in a statement.
The initial part sequencing of samples by INSACOG labs was aimed at detecting the Variants of Concern (VOC) among incoming international travellers and also to see whether any person with VOC has entered the country in past one month (double the incubation period of 28 days) from the date of establishment of INSACOG (December 26, 2020).
For the detection of presence of VOC inside country, five percent of the positives (by RT-PCR) were targeted for sequencing. Both the objectives were achieved by end of January, 2021, the statement said.
Many states like Maharashtra, Punjab and Delhi started showing rising trends in the month of February and as a response, the sequencing was enhanced in four districts of Vidharbha, 10 districts of Maharashtra and around 10 districts of Punjab, the statement said.
Moreover, the numbers have not been fixed to 300 samples per month or 10 sentinel sites per state. These are the indicative numbers and the States/UTs have been provided 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 statement stated.
Sentinel surveillance makes sure that samples from each state were geographically well represented as the five per cent 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 availability from the sentinel sites catering to districts with zero or single digit weekly new cases has also gone down. Currently, over 86 districts in the country are having zero weekly new cases, the statement said.
“For the past one month the majority of the new cases are from only Kerala and Maharashtra. At present, out of the total 45,000 new cases, more than 32,000 cases are from Kerala and more than 4000 cases from Maharashtra which means that 80 per cent cases are from two states and only 9000 cases, which is around 20 per cent, are from rest of the Indian states. “This is also reflected in the samples sequenced from various states,” the statement said. (PTI)
