A mutated and more aggressive strain of the novel coronavirus - which was first identified in the United Kingdom in September - has not been seen in India so far, the government said Tuesday. The new strain of the virus - that initial data suggests is at least 70 per cent more easily transmitted - has sparked concern worldwide, amid surging infection rates in the UK and fears that the first lot of Covid vaccines may not be as effective. "The new strain or mutation of (the) coronavirus seen in the United Kingdom has not been seen in India, so far," Dr VK Paul, a member of the government think-tank NITI Aayog, said.