The newly christened Delta variant or the B.1.617.2 strain, which originated in India, is behind the second surge of Covid in the country, a study by the Indian SARS-CoV-2 Consortium on Genomics (INSACOG) has found.
“B.1.617 variant & its lineage B.1.617.2 were primarily responsible for surge in cases with high transmissibility of 50 per cent more than Alpha variant (B.1.1.7),” said the study, indicating why India’s Covid ordeal in May was the worst witnessed in any country for any month since the beginning of the pandemic, both in terms of the absolute number of cases and fatalities.
India recorded nearly 90.3 lakh Covid cases in May month itself. The death toll from the pandemic in May was grimmer at nearly 1.2 lakh fatalities during the month (over 1,19,000), which was 2.5 times the toll reported in the country in April (48,768).
INSACOG is a grouping of ten National Laboratories established by the Union Health Ministry. The study was launched to investigate what caused the second surge.
The grouping is entrusted to carry out genomic sequencing and analysis of circulating Covid-19 viruses, and correlating epidemiological trends with genomic variants. So far, the genome sequencing of 29,000 samples has been done in India.
The B.1.617 has been found in 8,900 samples. More than 1,000 of those samples tested for the Delta variant.
Genomic variants of various viruses are a natural phenomenon and are found in almost all countries.
The names were given by the World Health Organization (WHO) recently stating that Covid-19 variants will now be known by letters of the Greek alphabet to avoid stigmatising nations where they were first detected.
The Covid variant B.1.617, first detected in India, is split into sub-lineages, of which the B.1.617.1 variant of interest becomes Kappa. The B.1.617.2 variant of concern is called Delta. Under the new system, the variants of concern take on the following names: the hitherto so-called British variant B.1.1.7 becomes Alpha; the B.1.351 first discovered in South Africa becomes Beta, while the Brazilian P.1 becomes Gamma.
“We know that the B.1.617.2, the Delta variant, does have increased transmissibility, which means it can spread easier between people,” WHO’s technical lead on Covid-19 Maria Van Kerkhove had said recently.