Tracking multiple coronavirus variants that have been active over time

Multiple coronavirus variants have been detected in the country since the pandemic took hold in March 2020, with Delta being the most devastating.

It accounted for a minority of the variants detected in January before the start of the second wave, shows data from tracker ‘Our World in Data’. But the share of the Delta variant samples began to climb steadily as the year progressed. Scientists analyse samples periodically to understand how the infection is changing and spreading.

It had a less than 10 per cent share in the analysed sequences in March 2021. This rose to over 90 per cent by May.

Other key strains identified in the country are — Beta, Epsilon, Gamma, Kappa, Iota, Eta, and Alpha. They were classified as variants of concern and variants of interest at different times. The latter means a variant which bears some watching, while the former refers to one gaining additional characteristics such as evidence of increased disease severity.

Mutant map

Variants of concern have been detected across continents but their designations — as a variant of concern — took varying amounts of time. For example, the Alpha variant was documented in the United Kingdom in September 2020. South Africa had detected the Beta variant in May 2020. Designation for both happened in December 2020. The earliest documentation of the Gamma variant was in Brazil in November 2020, but designation happened in January 2021.

India’s own delta variant was documented in October 2020, while designation as a variant of interest happened in April 2021. It was designated a variant of concern in May 2021.

“A previously designated variant of interest or variant of concern which has conclusively demonstrated to no longer pose a major added risk to global public health compared to other circulating SARS-CoV-2 variants, can be reclassified,” according to the WHO website.

A lack of capacity to conduct sequencing which will identify variants is a problem in many vulnerable countries, according to an April 2021 piece entitled ‘Rapid identification and tracking of SARS-CoV-2 variants of concern’ from authors Debojyoti Chakraborty, Anurag Agrawal and Souvik Maiti published in medical journal The Lancet.

“Even in those low-income and middle-income countries where such capacity is present and high alert is in place, the delay between positive diagnosis and sequencing results leads to an opportunity for a new variant to become established,” it said.

Newer technologies could accelerate the process, according to the authors who had suggested the use of clustered interspaced short palindromic repeats diagnostics at the time.