Covid-19: Delta Plus is now variant of concern in India

The Delta Plus variant of the SARS-CoV-2 virus has been elevated to variant of concern (VOC) in the country. The total number of Delta Plus infections in the country are up to 40. This viral variant also known as AY.1 has also been seen in nine other countries of the world with 205 infections detected in Europe, America and Asia.

The SARS-CoV-2 virus causing Covid-19 disease is mutating continuously with the number of infections rising across the world and in India. Mutations help the virus to become either more transmissible or more virulent or both.

INSACOG, a consortium of 28 labs, established by the health ministry to carry out genome sequencing of the virus causing the Covid pandemic, had identified the viral variant (Delta B.1.617.2). According to INSACOG, currently the number of such Delta Plus variants in India are only few, but the distribution and detection in various states during past two months indicate that the AY.1 or B.1.617.2.1 was already present in some states. The role of AY.1 in immune escape, disease severity or increased transmissibility is under continued surveillance.

Among the 45,000 samples sequenced in India, this variant has been observed in Maharashtra, Kerala and Madhya Pradesh. INSACOG has emphasised on the need to enhance their public health response by focusing on surveillance, enhanced testing, quick contact-tracing and priority vaccination in defined geographies where AY.1 has been detected, the health ministry has said.

The health ministry had said on Tuesday, that the Delta Plus cases was found in Ratnagiri and Jalgaon districts of Maharashtra, Palakkad and Pathanamthitta districts of Kerala and in Madhya Pradesh’s Bhopal and Shivpuri districts. The states have been advised to take up immediate containment measures in the districts and clusters identified by INSACOG.

The health ministry has advised the state governments of Maharashtra, Kerala and Madhya Pradesh to send adequate samples of positive persons to designated laboratories of INSACOG so that the clinical epidemiological correlations could be made. These states have been advised to strengthen surveillance and prevent crowds, intermingling of people, carry out widespread testing, prompt tracing as well as increase vaccine coverage on a priority basis.

The mutations of the variants are known as variants of interest (VOI) and when the variant increase in frequency in the selected population it is then considered then as variants of concern (VOC). With evolution of several variants around the globe, the World Health Organization introduced the VOC and VOI classification. The Delta variant as well as all Delta sub-lineages including Delta Plus are classified as VOC by the WHO.

INSACOG reported the evolution of Delta Plus variant (B.1.617.2) + K417N lineage of SARS-CoV2 (called as B.1.617.2.1/ AY.1). The Delta Plus variant known as AY.1 or B.1.617.2.1 is characterised by the K417N mutation in spike protein. Apart from the AY.1 mutation, the Delta Plus variant has another mutation called AY.2. This was found in sequences uploaded from the US.

At present, the first mutation is seen in India and second mutation has not yet been found here. INSACOG is investigating all Delta sub-lineages and treating it as a VOC. The properties of AY.1 are still being investigated.

The K417N mutation has been of interest because it is present in the Beta variant (B.1.351 lineage), which was reported to have immune evasion property so it could dodge vaccines and antibodies.