'Delta' variant behind second COVID-19 wave in India, 50% more transmissible: NCDC study

In the first study of India's second COVID-19 wave, the National Centre for Disease Control (NCDC) and scientists of INSACOG have zeroed down the Delta variant (B.1.617) as the cause behind the surge. The study stated that B.1.617 variant & its lineage B.1.617.2 were primarily responsible for surge in cases with high transmissibility of 50% more than Alpha variant (B.1.1.7). Currently, India has 16,35,993 active cases, 2,65,97,655 recovered cases and 3,40,702 fatalities.

India's Delta variant behind case surge: NCDC

The study which is still ongoing, says there are more than 12,200 "Variants of Concern" in the country, as revealed by genomic sequencing, but their presence is minuscule compared to the Delta variant. Moreover, scientists have found no evidence of the Delta variant in the higher severity of cases and higher fatalities. The variant which is found in all states is mainly prevalent in Delhi, Andhra Pradesh, Gujarat, Maharashtra, Odisha and Telangana. No traces of the alpha variant has been found yet, revealed the study. Of the 29,000 Covid case samples which have undergone genome sequencing the B.1.617 variant was found in 8900 samples.

WHO dubs B.1.617.1 as Delta variant

On Monday, the World Health Organisation (WHO) announced that the B.1.617.1 and B.1.617.2 variants of the COVID-19, first identified in India, has been named as 'Kappa' and 'Delta' respectively. This move came weeks after Centre ordered all social media platforms to 'remove all content referring or implying to the 'Indian variant' immediately. The Centre cited the recent clarification issued by World Health Organisation (WHO) stating that the B.1.617.2 variant found in India was not classified as the 'Indian variant'.

WHO has classified the B.1.617 variant of the Coronavirus, first identified in India, as a variant of global concern. As of 11 May, over 4500 sequences were uploaded to GISAID and assigned to B.1.617 from 44 countries in all six WHO regions, and WHO has received reports of detections from five additional countries. WHO stated that the B.1.617 sublineages appear to have higher rates of transmission, including observed rapid increases in prevalence in multiple countries.

Viruses in the B.1.617 lineage were first reported in India in October 2020 with a recent WHO risk assessment finding that resurgence and acceleration of COVID-19 transmission in India had several potential contributing factors including political mass gathering, reduced adherance to social measures. Approximately 0.1% of positive samples in India have been sequenced and uploaded to GISAID to identify SARS-CoV-2 variants. The WHO has assured that all existing treatments, vaccines and diagnostics continue to remain effective against the  B.1.617 variant of the Coronavirus.