‘Delta variant up to 60% more transmissible than Alpha’

Our Bureau New Delhi | Updated on July 19, 2021

The variant may have caused the recent spurt in Covid-19 cases, says NK Arora

Delta variant, also known as B.1.617.2, responsible largely for the second wave of the pandemic, is 40-60 per cent more transmissible than its predecessor, the Alpha variant, and has already spread to more than 80 countries, including the UK, the US and Singapore, said NK Arora, co-chair, Indian SARS-CoV-2 Genomics Consortium (INSACOG), on Monday.

It accounted for 80 per cent of the cases during the second wave, he said in a statement issued by the Health Ministry. Delta variant, first identified in October 2020 in India, has mutations on its spike protein, which help it bind more firmly to the ACE2 receptors present on the surface of the cells, making it more transmissible and capable of evading the body’s immunity, said Arora.

“On invading a human cell, it replicates faster. It leads to a strong inflammatory response in organs like the lungs. However, it is difficult to say that disease due to Delta variant is more severe. The age profile and deaths during the second wave in India were quite similar to that seen during first wave,” Arora added.

Delta Plus variant

Meanwhile, the Delta Plus variant (AY.1 and AY2), which is a mutation of the Delta variant, has been detected in 55-60 cases across 11 States, including Maharashtra, Tamil Nadu, and Madhya Pradesh, said Arora.

He further said that AY.1 is also found in countries such as Nepal, Portugal, Switzerland, Poland and Japan, but AY.2 is less prevalent. The variant is still being studied for its transmissibility, virulence, and vaccines escape characteristics.

Arora also stated that the current vaccines are effective against the Delta variant, as per the studies undertaken by the Indian Council of Medical Research (ICMR).

According to Arora, a recent spurt in Covid cases, especially in the north-eastern region and many districts in the southern region, may be due to the Delta variant. “A virus begins infecting a part of the population, which is most susceptible and also exposed to the infection. It diminishes after it successfully infects a large proportion of the population and strikes back when the immunity developed in the people post-natural infection fades. The cases may go up if a new, more infectious variant come,” Arora further added.

Third wave

On the third wave, Arora said future waves can be controlled and delayed if more and more people get vaccinated and, most importantly, by following Covid-appropriate behaviour effectively, especially till a substantial part of the population gets vaccinated.

Published on July 19, 2021

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