Existing in the shadow of the rapidly-spread COVID-19 delta variant, a new study highlights that we should also take note of the potential threat by another emerging strain, the Lambda variant.
A new study conducted by Japanese researchers from the University of Tokyo was able to identify three genetic mutations in the spike protein of the new coronavirus strain. These genetic differences supposedly help the Lambda variant resist the body's newfound defenses from the vaccine antibodies.
The University of Tokyo researchers have uploaded their efforts on the online repository BiorXiv last July 18, still awaiting peer review before being published. The preprint currently available is titled "SARS-CoV-2 Lambda Variant Exhibits Higher Infectivity and Immune Resistance."
What Makes the Lambda Variant Potentially More Dangerous
According to the preprint from the University of Tokyo, the Lambda variant is potentially more infectious because of its T76I and L452Q mutations. A third mutation, found in RSYLTPGD246-253N, is reported as a unique seven amino acid deletion mutation in the N-terminal domain. The third mutation is responsible for the new COVID-19 strain evading neutralizing antibodies created by the vaccinated host.
To identify what made the new variant unique, researchers generated a maximum likelihood-based phylogenetic tree of the Lambda variant. Their phylogenetic tree was developed from a dataset of 1,908 genome sequences available as of June 29, 2021. Researchers additionally noted that while the WHO report first formally detected the Lambda variant in Peru in December 2020, a deeper analysis of the available data suggests that the new strain was actually first detected in Argentina on November 8, 2020.
Also, while they were open to the possibility of isolates that might be misclassified in the dataset, researchers expressed confidence that the tree shows the monophyly of legitimate Lambda variant isolates.
Virological tests conducted on the various strains showed that the large deletion RSYLTPGD246-253N, does not affect the Lambda variant's ability to spread and infect others. However, it is largely responsible for the new strain's resistance to the vaccine-induced antibodies.
The Next Step Against the Rising Strain
The Lambda variant has been spreading across 29 countries from five separate regions of the World Health Organization since it was first found in Peru as early as August 2020. It has also been recorded in the US, with separate cases in Texas and South Carolina, leading to the new strain being a 'variant of interest.'
Additionally, the new findings from the University of Tokyo study match with the results of a previously released study, also awaiting peer review, conducted by a team from Chile. Medical researchers from the University of Chile, in a medRxiv preprint, show the increased infectivity from the Lambda spike protein, being more infectious than the D614 G(lineage B) strain as well as the Alpha and Gamma variants of the disease.
Despite this spread, Japanese researchers said that the threat surrounding the new variant remains underestimated since it is only referred to as a "variant of interest" or a "variant of concern."
"Lambda can be a potential threat to the human society," said Kei Sato, a senior researcher from the University of Tokyo, in an interview with Reuters.
A consistently proven method of facing the Lambda variant remains to be found. Additionally, a separate preprint on bioRxiv by Rockefeller University researchers suggests that the third dose of mRNA vaccine from Pfizer or Moderna could increase the antibody levels in the body, but that does not mean that more means better in the battle against the ever-changing COVID-19 variants.
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