Columbia study warns that COVID-19 KP.3.1.1 and XEC variants are highly immune evasive than even JN.1 or KP.3
Nikhil Prasad Fact checked by:Thailand Medical News Team Nov 20, 2024 1 hour, 57 minutes ago
Medical News: The COVID-19 virus continues to evolve, introducing new variants that challenge existing immunity and public health strategies. In a recent study conducted by researchers from Columbia University's Aaron Diamond AIDS Research Center along with assistance from scientists from the University of Michigan, alarming insights have emerged regarding two new SARS-CoV-2 subvariants: KP.3.1.1 and XEC. These variants, according to the researchers, exhibit a higher level of immune evasiveness than their predecessors, including the JN.1 and KP.3 variants. The implications are that people who only just recently got infected by the JN.1 and KP.3 strains could possibly get reinfected by the newer KP.3.1.1 and XEC strains easily. Furthermore, the degree of protection from the current new boosters being promoted by various health authorities around the world are also being questioned as the study findings prove contentious issues.
C
olumbia study warns that COVID-19 KP.3.1.1 and XEC variants are highly immune
evasive than even JN.1 or KP.3
This
Medical News report dives deep into the study findings, shedding light on the evolutionary advancements of these variants and their implications for global health. With KP.3.1.1 now being the most prevalent variant worldwide and XEC showing the fastest growth rate, understanding their behavior is critical to managing the pandemic's next phase.
The Rising Threat of KP.3.1.1 and XEC Variants
KP.3.1.1 and XEC are not just new names in the long list of SARS-CoV-2 variants; they represent a significant leap in the virus's ability to evade human immunity. KP.3.1.1, which evolved from the KP.3 lineage, carries a unique spike mutation (S31∆) that enhances its immune resistance. Meanwhile, XEC, a recombinant variant of JN.1 sublineages KS.1 and KP.3.3, introduces additional mutations in the spike protein's N-terminal domain (NTD), specifically T22N and F59S.
The researchers conducted comprehensive laboratory tests to assess how these variants interact with human immune defenses. By analyzing serum samples from individuals previously infected with JN.1 and those vaccinated with updated KP.2-based mRNA boosters, the study revealed that KP.3.1.1 and XEC were 1.3-1.6 times more resistant to neutralization compared to KP.3. This resistance directly contributes to their growing dominance across populations.
Antigenic Mapping and Immune Escape
One of the study's groundbreaking aspects was its use of antigenic mapping to visualize the immune evasion strategies of these variants. The findings highlighted that KP.3.1.1 and XEC cluster closely together in their antigenic properties, standing apart from earlier variants like JN.1. This clustering is a result of the mutations in their spike proteins, which enhance their ability to bypass antibodies targeting the virus's receptor-binding domain (RBD).
Interestingly, the study also tested monoclonal antibodies and soluble human ACE2 receptor inhibition against these variants. The S31∆ and
F59S mutations were found to interfere with the virus's spike structure, reducing the efficacy of neutralizing antibodies and ACE2 binding. These mutations impair the upward motion of the RBD, which is crucial for effective antibody binding, giving the virus a distinct advantage.
What Sets KP.3.1.1 and XEC Apart?
Unlike other variants, KP.3.1.1 and XEC employ unique mechanisms for immune escape:
-Spike Mutations: Both variants possess mutations that alter the NTD and RBD of the spike protein. These changes hinder antibody attachment and spike conformational changes, reducing immune recognition.
-Monoclonal Antibody Resistance: The variants show resistance to key monoclonal antibodies, including C17173 and others targeting RBD class 4/1 epitopes. This resistance complicates treatment options for severe COVID-19 cases.
-Lower Affinity for ACE2: The mutations also affect the virus's binding affinity for the ACE2 receptor, which paradoxically helps it evade neutralization while maintaining infectivity.
Study Implications and Future Directions
The researchers, led by Dr. David D. Ho of Columbia University, emphasized that these variants' immune evasiveness poses a significant challenge for vaccine development and therapeutic interventions. The findings underscore the urgent need to update COVID-19 vaccines to include these emerging variants, ensuring broader protection against the virus.
Furthermore, the study's detailed analysis of antigenic properties provides valuable insights for designing next-generation monoclonal antibodies. By targeting regions of the spike protein less affected by these mutations, future treatments could potentially overcome the resistance seen in KP.3.1.1 and XEC.
Conclusion
The Columbia and Michigan team has sounded an important alarm with their study. As KP.3.1.1 and XEC continue to spread globally, their ability to evade immune defenses highlights the evolving nature of the pandemic. These variants remind us that SARS-CoV-2 is far from static, and our response strategies must adapt quickly to keep pace.
While current vaccines and treatments offer some protection, the findings make it clear that innovation is needed to stay ahead of the virus. Global cooperation in surveillance, vaccine development, and public health measures will be crucial to mitigating the impact of these new variants.
The study findings were published on a preprint server and are currently being peer reviewed.
https://www.biorxiv.org/content/10.1101/2024.11.17.624037v1
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