Second Covid-19 wave in Karnataka largely driven by Delta variant, say experts

This strain has been labeled a variant-of-concern by the World Health Organisation

Scientists have found that a majority of people with Covid-19 have been infected with the so-called “Delta” double-mutant variant of the novel coronavirus.

Recent sequencing of samples from 44 symptomatic individuals at HCG Strand Labs found that 41 of the patients had been infected with the B.1.617.2 “Delta” variant of the virus. This strain has been labeled a variant-of-concern (VoC) by the World Health Organisation because of its ability to evade an immune system response.

Questions now arise about whether this variant is responsible for the high influx of cases in the second wave and potentially, the manifestation of more serious cases requiring hospitalisation.

According to Dr Vishal Rao, Dean, Centre of Academic Research, HCG Cancer Hospital, the fact that 93 per cent of randomly tested individuals had the “Delta” variant suggests that the second wave is largely being driven by this version of the novel coronavirus.

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On whether it is causing aggravated effects is something that the virologist and Technical Advisory Committee member, Dr V Ravi, formerly of Nimhans, said was not borne out by the evidence. “It is true that the “Delta” variant is taking over in the state, even over its sister variant, the B.1.617.1 (‘Kappa’) which has been identified as a variant of interest (VoI). But to say that hospital cases have all been infected with the “Delta” is not true. There are many others infected with the “Delta” who do not require hospitalization,” he said.

Officially, the state has recorded 244 cases of people infected with B.1.617 variant, which includes “Delta” and 1.617.1 “Kappa.” Deputy Chief Minister, Ashwath Narayan, who was briefed on the sequencing results on Friday told DH that genomic sequencing must go hand-in-hand with testing. It also could prompt an altering of treatment protocols, he added.

Although the state government had constituted a genomic sequencing committee last year, much of the impetus to expand genomic sequencing was stalled after the first wave ended. The DyCM said that has now been reversed. “We are starting or supporting seven sequencing labs across the state, including at the Indian Institute of Science (IISc) and the National Centre for Biological Sciences (NCBS), which will help ramp up sequencing,” he added.

Meanwhile, Dr Rao said that phase two of the sequencing trials will cover ICU patients.

“The “Delta” variant was first identified globally in December 2020, but we only introduced a lockdown four months later in April 2021. This shows that there were delays in identifying the variant locally,” he said.