N440K variant 10 times more infectious, fuelling Covid surge

The N440K can generate about ten times more virus particles than the A2a prototype, the strain which is in circulation worldwide

Hyderabad: The N440K variant of the SARS-CoV-2, which is geographically spread across Telangana, Karnataka, Chhattisgarh and Maharashtra, has the ability to generate large amounts of infectious virus particles within a short time and capable of rapid spread across the population, which gives it an edge over other mutations, a new study by geneticists from Centre for Cellular and Molecular Biology (CCMB), said.

The CCMB study on the N440K variant also explains the reason behind the rapid surge of Covid infections in Telangana during the second wave, especially in April that saw the rise of active cases from just 6,159 to 80,000 within just one month.

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The N440K can generate about ten times more virus particles than the A2a prototype, the strain which is in circulation worldwide. This ability to generate larger amounts of infectious virus particles in a short time makes N440K distinctive over other mutations, the CCMB study said.

“Our studies unambiguously demonstrate that N440K variant has the capacity to generate significantly higher and more infectious virus particles in shorter duration. The study suggests that this feature could promote its faster spread among certain populations. We predict that the higher infectivity achieved by the N440K variant could possibly lead to its higher rate of transmission,” the study said.

The research, which is available online in its preprint version at bioRxiv from April 30, analysed the prevalence, replicative fitness and infectivity of N440K. “The variant produced 10 times higher infectious titers than a prevalent A2a strain and over 1,000 folds higher titers than the much less prevalent a3i strain prototype,” researchers said.

The N440K mutation has been suspected to be responsible for super-infections and quick spread of the infection in certain pockets. The mutation has been reported in several viral sequences across India, especially between March and April 2021 in Telangana, Karnataka, Chhattisgarh and Maharashtra. In their study, the CCMB researchers have found out that there has been a gradual increase in the representation of the N440K variant between March and April, adding more of this variant than the previous months.

“An increase in the proportion of N440K variant in the Indian samples is also evident with almost 10 per cent of the sequences submitted in April carrying this substitution. Karnataka, Maharashtra, Telangana and Chhattisgarh together contributed to about 50 per cent of these samples indicating the geographically localized spread of this variant in India,” researchers said. The study was take-up by CCMB in collaboration with the Academy of Scientific and Innovative Research (AcSIR), Ghaziabad.

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