Coronavirus: Delta variant of Covid-19 found in 174 districts across 35 states

INSACOG is a consortium of 28 genome sequencing laboratories carrying out sequencing and analysis of the Covid-19 virus to understand the spread and evolution of the SARS CoV-2, its mutations and resulting variants as well as ascertaining the status of the variants.

The Delta variant of the Covid-19 virus has been found in 174 districts across 35 states by the Indian SARS-CoV-2 Genomics Consortium (INSACOG). The Delta variant has been declared as a Variant of Concern (VOC) and the highest incidence of this version has been reported from districts in Maharashtra, Delhi, Punjab, Telangana, West Bengal & Gujarat.

The Delta Plus is a variant of the Delta virus with an additional mutation (B.1.617.2.1 or AY.1). Alpha, Beta and Gamma are the other variants detected in India. The AY.1 was first observed in Maharashtra and is being associated with the unusual rise in cases seen in several districts of the state. It is now found in many other states in the country. According to the health ministry, there are 51 cases of Delta Plus found in 12 states in the country including Maharashtra, Punjab, Gujarat, Kerala, Andhra, Tamil Nadu, Odisha, Rajasthan, Jammu, Karnataka and Haryana.

INSACOG is a consortium of 28 genome sequencing laboratories carrying out sequencing and analysis of the Covid-19 virus to understand the spread and evolution of the SARS CoV-2, its mutations and resulting variants as well as ascertaining the status of the variants. INSACOG’s sentinel surveillance and surge surveillance mechanisms are expected to help in the early detection of genomic variants and formulate public health responses.

India started sequencing SARS-CoV-2 viral genomes in December 2020. The initial focus of India was on restricting the spread of global variants of concern in the country – Alpha (B.1.1.7), Beta (B.1.351) and Gamma (P.1), which had high transmissibility. These variants were tracked by INSACOG. Subsequently, the Delta and Delta Plus variants were also identified based on whole-genome sequencing analysis.

Initially, genomic surveillance was focused on the variants carried by international travellers and their contacts in the community through sequencing 3-5% of the total RTPCR positive samples. Subsequently, the sentinel surveillance strategy was adopted with multiple sentinel sites across the country for a wider geographic spread. RTPCR positive samples are sent from each sentinel site for sequencing.