INSACOG finds new ways for Covid-19 sampling amid a low case count

Plans afoot to expand INSACOG to South Asian countries

India is continuing to sequence samples of the Sars-Cov-2 virus despite a low case count of Covid-19 in the country.

The Indian Sars-CoV-2 Genomics Consortium (INSACOG), set up under the health ministry, is not letting its guard down and also plans to expand the network to South Asian countries and collaborate to monitor the virus.

At a time when daily fresh case counts are below the 2,000 mark for a while now, India is sampling 100,000-150,000 samples from patients with severe acute respiratory infection (SARI), said N K Arora, co-chair of INSACOG and also chairman of the Covid-19 working group, National Technical Advisory Group on Immunisation (NTAGI).

“INSACOG is a new system that we developed during the pandemic and its role becomes even more significant now. The network has to follow the evolution of the virus very closely, and also lay the foundation for what to expect from a future pandemic,” Arora told Business Standard. He added that India plans to widen the INSACOG network to collaborate with South Asian countries for a more robust monitoring of the virus.

He said various types of surveillance were on — such as sewage sampling, sampling of hospitalised Covid-19 patients, and SARI sampling.

“We are doing genomic sampling of hospitalised Covid-19 patients from the sentinel hospital sites. We are also continuing with sewage sampling and on top of this we are collecting samples from SARI patients for genomic sequencing,” Arora said.

Overall, INSACOG is still processing 8,000-9,000 samples every week now, he added. As for SARI, India is sampling around 100,000-150,000 patients every day through its public surveillance network. “Of this, around 1 per cent of the patients are turning out to be Covid-19 positive. We are conducting genomic sequencing for all such samples,” Arora explained.

Sewage sampling was started earlier this year. It is called environmental surveillance and India had done this during the polio campaign. Not many countries have the technology and capability to detect virus particles from sewage water.

The protocol has been set methodically and is being used to see the virus’ circulation in the environment. Many Covid-19 infected people now are either asymptomatic or have very mild influenza-like symptoms. Therefore, many are not opting for testing through RT-PCR anymore.

So, the samples available for genomic sequencing by INSACOG are going down, and thus it is imperative to go for environmental surveillance. It also helps to pick up dominant strains in the population, and any geographical trends in the infection scenario.

Arora said that the Omicron variant of the Sars-CoV-2 has had around 70 sub-variants and their descendents that are in circulation. “The virus is here to stay, and it will co-exist with human beings,” Arora explained, adding that it is impossible to say now whether we would have another variant of concern in the near future.

“That is why it is important to monitor the virus’ evolution. Moreover, one can expect to see another pandemic in the not so distant future,” he said.

So far, Omicron and its sub-lineages continue to be the dominant variant in India. BA.2 and BA.2.75 are the most common variants in several parts of India. In the US, BA.5 was the dominant sub-variant of Omicron, but by October it gave way to BQ.1 and BQ.1.1.

INSACOG is keeping a close watch on the evolution of XBB and XBB.1 and any new sub-lineages in India.

ON GUARD

·         100,000-150,000 SARI samples picked up every day

·         Of these, 1% is typically Covid-19 positive

·         Positive samples are sent for genomic sequencing

·         Covid-19 positive patients in sentinel hospital sites sent for genomic sequencing

·         Sewage water sampling continues at sentinel sites

·         8,000-9,000 samples now tested every week by INSACOG

·         India plans to expand INSACOG to South Asian countries