Hyderabad: 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.
In an exclusive chat with ThePrint, 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.”
According to CCMB’s Vishal Shah, one of the authors of the pre-print, the study did not compare the infective tier of N440K with the B.1.17 UK variant or the B.1.617 Indian variant in this study. The comparison was with its parent variant, which did not have N440K mutation and with another variant that is now almost lost among the population.
We did not compare the infective titer of N440K with UK or double mutant in this study. We compared it with its parent strain which did not have N440K mutation and with another strain which is now almost lost among the population.
— Vishal Sah (@acurious_one) May 4, 2021
The study spoke about the N440K variant (also known as B.1.36) being more infectious than its parent lineage A2a ( also known as D614G mutant or B.1.1.8) and an unrelated A3i variant (aka B.6).
So a few days back we published a preprint from our lab that N440K variant (also known as B.1.36) has more infectious fitness than its parent lineage A2a ( also known as D614G mutant or B.1.1.8) and an unrelated A3i variant (aka B.6)
— Vishal Sah (@acurious_one) May 4, 2021
“We did not compare the infective titer of N440K with the UK or double mutant in this study,” he tweeted late Tuesday. “We compared it with its parent strain which did not have N440K mutation and with another strain which is now almost lost among the population… nowhere in the study was it said that N440K is deadliest or it is more dangerous than the UK or double mutant variant.”
We did not compare the infective titer of N440K with UK or double mutant in this study. We compared it with its parent strain which did not have N440K mutation and with another strain which is now almost lost among the population.
— Vishal Sah (@acurious_one) May 4, 2021
Incubation period shorter, progression faster in Vizag: Doctors
According to Dr P.V. Sudhakar, the Visakhapatnam district Covid-19 special officer and principal of the Andhra Medical College, the incubation period is shorter, progression of infection leading to severe symptoms is faster in patients infected with Covid-19 in Visakhapatnam.
He also said that there is no way to quantify if the variant was being more virulent or deadly.
“There are some medical observations that I saw but that does not mean we can quantify and say a strain is more virulent,” Sudhakar said.
“However, we have observed that once infected, the incubation period seems shorter in patients. Unlike before, people are developing breathlessness in two days of being infected. So, the progression is faster.”
He also added that it has been observed that “younger people, fitness freaks, children and women” are also easily being infected.
“So irrespective of age or immunity levels, we’ve observed that the spread is faster, magnitude of the infection is more and people are reaching hypoxia or dyspnea stage early,” he said. “But that does not mean we can quantify and say it is so many times more virulent unless studies are conducted. We just gave our first hand observations to the team.”
Irrespective of the variant, the clinical treatment would mostly be the same. The identification of variants would only be helpful in understanding whether the vaccine would work or if there are any new symptoms or heavier infection, Sudhakar added.
According to CCMB, Andhra Pradesh has nothing to be specifically concerned about and the usual precautions and vaccination must be efficiently implemented.
“We are not saying Andhra or any state can relax; we are in the second wave and have seen how fast the spread is,” a source from CCMB told ThePrint. “So, whatever measures the state has been taking and whatever suggestions are being given by experts should be implemented well. We’re sending a formal clarification to AP.”
(Edited by Arun Prashanth)
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