The Delta variant was the prime driver behind the deadly second wave of coronavirus that struck the country between March and May.
The Delta Plus variant of SARS-CoV2 has been detected in 86 samples in the country so far and it has not led to any exponential surge in cases, the government said on Tuesday.
“We found the Delta Plus variant in 86 (genome) samples (sequenced),” Sujit Singh, head of the National Centre for Disease Control (NCDC), said at the health ministry’s press briefing.
He said four types of variants are categorised as Delta Plus — AY1 (B.1.617.2.1), AY2, AY3 and one more sub-lineage — in which one more gene has been detected and its only sample was found in Maharashtra.
He said the highest number of 34 samples were detected in Maharashtra, followed by Madhya Pradesh (11) and Tamil Nadu (10).
“The detection of 86 samples since March from different places, with no surge (of cases recorded) in any district (due to it), or restricting it to any specific state indicates that this (Delta Plus variant) does not have the capacity to give rise to any exponential surge. We have not found any (such) evidence.
“This variant, through its transmission, has not led to any major exponential surge,” Singh said.
“There is no evidence of adverse effects of over and above the Delta variant,” V K Paul, Member (Health), Niti Aayog, said.
Singh said 80-90 per cent of the samples sequenced in all the INSACOG laboratories were of the Delta variant.
INSACOG is a consortium of laboratories of the Indian Council of Medical Research (ICMR), the Department of Science and Technology (DST), the Council for Scientific and Industrial Research (CSIR) and the Department of Biotechnology (DBT).
Paul said the Delta variant is “ruling the nation and the world” and many countries have been witnessing a surge in COVID-19 cases due to it.
The Delta variant was the prime driver behind the deadly second wave of coronavirus that struck the country between March and May. It overwhelmed the health infrastructure, claimed thousands of lives and infected lakhs of people.
Citing a World Health Organization (WHO) report, Paul said the transmissibility and attack rate of the Delta variant are higher than the other variants of the virus.
If the transmission rate of the original SARS-CoV2 virus is 100, that of the Alpha variant, which originated in the UK, was 60 per cent higher than the original one. Delta’s attack rate is 60 per cent higher than that of Alpha, Paul explained.
The viral load of the Delta variant is more and it increases the chances of hospitalisation, he said.
Paul, however, added that vaccines help prevent severe disease and mortality against this variant.
Singh said the INSACOG network has sequenced 58,240 samples. The B.1.617.3 and Kappa variants are under investigation, he added.
Singh said for any new variant, a rapid response strategy is devised and directions are issued to the states.
When a new mutant is detected by a laboratory, its tracking and contact-tracing should be done at a rapid pace, he added.
Singh said the states have been requested to form rapid response teams at the medical college level. Many states have started implementing it, he added.
The teams will contact a patient. The teams will have a microbiologist, a public health expert and a clinician who will check the severity of the disease. The team will take additional samples and send those for sequencing and also determine the severity of the disease and the kind of public health impact the new mutant is giving rise to.