The Hyderabad based Centre for Cellular and Molecular Biology (CCMB) Wednesday debunked reports of a unique or a novel strain circulating in Andhra Pradesh, particularly in Visakhapatnam. CCMB director, Rakesh Mishra, said the prevalence of the variant being called the ‘N440K strain’ in Andhra Pradesh is less than 5 per cent at the moment and is likely to disappear or be replaced soon by other existing variants.
He also said that there is no evidence that the N440K variant is deadly or more infectious than other Covid-19 variants. “There is no unique AP strain or a Vishakapatnam strain. Neither were any existing strains found to be more infectious or deadly than what we already saw before,” Mishra said.
“The N440K has been around for quite some time and was prevalent in other southern states (Karnataka, Kerala) earlier. But now the N440K in Andhra is less than 5 per cent and is likely to be replaced by a double mutant or any other variant. It could have been around during the first wave also.”
The N440K is a mutation, where the N amino acid at the 440th position of the spike protein changed to the K. The mutation is a part of a number of variants globally, and is associated with immune escape. The CCMB had, in February, said that there was emerging evidence that the N440K mutation is spreading a lot more in southern states and a closer surveillance is needed to understand its spread properly.
Also denying that the variant is 15 times more virulent in Andhra Pradesh, Mishra said that it would be a misinterpretation to claim so. Citing a pre-print published by the lab a few days ago, which spoke about how the N440K variant grows faster in a ‘culture’, the director said that does not mean it is more virulent in humans.
“There was some misinterpretation — our report said the virus grows 10 or 15 times more when grown in a culture. But culture is a different kind of animal cell that we grow and in that, we replicate the virus and the yield is more,” he added. “That does not reflect infectivity in humans. Because humans are whole systems; they have immune systems and a lot of other variations. So, infectivity cannot be compared to what happens in a culture cell.”