The Delta variant (or B.1.617.2 strain) of the coronavirus was “primarily responsible” for the second wave of Covid-19 in India, Dr NK Arora, co-chair of the Indian SARS-CoV-2 Genomics Consortium (INSACOG) said on Monday.
While he said that the vaccines currently in use for the immunisation were effective against the variant, citing studies by the Indian Council of Medical Research (ICMR), nevertheless, he underlined that the cases may go up if a new, more infectious variant comes. The variant is also around 40-60 percent more transmissible than its predecessor, Alpha variant, and has already spread to more than 80 countries, including the UK, the US and Singapore.
“B.1.617.2, a variant of Covid-19 is known as the Delta variant. It was first identified in October 2020 in India, and was primarily responsible for the second wave in the country, today accounting for over 80 per cent of new Covid-19 cases. It emerged in Maharashtra and travelled northwards along the western states of the country before entering the central and the eastern states,” Dr Arora said.
The Delta Plus variant—AY.1 and AY.2—has so far been detected in 55-60 cases across 11 states, including Maharashtra, Tamil Nadu, and Madhya Pradesh and is still being studied for its transmissibility, virulence, and vaccine escape characteristics, Dr Arora said, according to a Union Health Ministry statement. The Delta variant has mutations in its spike protein, which helps it bind to the ACE2 receptors present on the surface of the cells more firmly, making it more transmissible and capable of evading the body’s immunity, Dr Arora said.
On whether it causes more severe disease as compared to other variants, Dr Arora said there are studies that show that there are some mutations in this variant that promote syncytium formation.
Dr Arora said current vaccines are effective against Delta variant as per the studies undertaken by ICMR on the issue. On some parts of the country still witnessing a spurt in the number of cases, he said, though there is a significant dip in the number of cases in most parts of the country, some regions are witnessing a high-Test Positivity Rate (TPR) particularly in the north-eastern part and several districts in the southern states, most of these cases could be due to the Delta variant.
Whether future waves could be prevented, Dr Arora said ,”The cases may go up if a new, more infectious variant comes. In other words, next wave will be driven by a virus variant to which a significant proportion of population is susceptible.”
The second wave is still going on. Any future waves will be controlled and delayed if more and more people get vaccinated and most importantly, people follow COVID-Appropriate Behaviour effectively, especially till a substantial part of our population gets vaccinated, he stressed.