March 1, 2024

Lukmaan IAS

A Blog for IAS Examination




THE CONTEXT: The emergence of the omicron subvariant JN.1 has raised concerns due to its unique mutation in the spike protein, specifically the L455S, referred to as a “FLip” mutation.


  • Researchers at the University of Tokyo have indicated that this mutation might facilitate evading immunity and contribute to a surge in COVID-19 cases.

Evolution from BA.2.86 Lineage to JN.1

  • 1, an offshoot of the BA.2.86 lineage, swiftly gained dominance globally, characterized by its spike protein mutation and surpassing other omicron sublineages like EG.5.1 and HK.3.
  • It’s noteworthy that JN.1’s rise doesn’t inherently denote increased danger but rather reflects the virus’s natural propensity to mutate.

Understanding “FLip” Mutations and Impact on Transmissibility

  • The “FLip” mutations – L455S, L455F, and F456L – significantly alter the spike protein’s structure, enhancing the virus’s binding affinity to ACE2 receptors.
  • This elevated binding potentially leads to increased transmissibility, as observed in the JN.1 lineage, outcompeting other variants.

Virological Insights and Transmissibility

  • Research from Peking University in The Lancet Infectious Diseases revealed that JN.1, with the L455S mutation, rapidly dominated over its predecessor 2.86.
    • It strains with the “FLip” mutations, showcasing a higher effective reproductive number (Re), indicating increased transmissibility.

Implications on Immunity and Vaccination

  • Studies from Biomedical Pioneering Innovation Center (BIOPIC) suggest that JN.1 exhibits a heightened ability to evade immunity.
  • It is evident from individuals experiencing breakthrough infections post-vaccination or reinfections after prior omicron lineage infections.
  • This raises concerns about potential vaccine evasion and the need for further vigilance.

Global Scenario and Public Health Concerns

  • Globally, an increase in COVID-19 cases and a decrease in deaths have been reported.
  • However, the accuracy of reported cases is affected by reduced testing and integrated reporting methods.
  • This situation underscores the importance of continued vigilance and improved surveillance.

Regional Impact and Response

  • Specifically, India observed a notable rise in cases within the Southeast Asia region, emphasizing the necessity for targeted responses, especially for vulnerable populations such as the elderly, those with comorbidities, and immunocompromised individuals.

CDC’s Assessment and Cautionary Measures

  • The Centers for Disease Control and Prevention (CDC) in the United States flagged the escalating prevalence of JN.1 globally.
  • While acknowledging its potential for increased transmissibility or immune evasion, the CDC cautioned that it’s premature to gauge the extent of its impact on infections or hospitalizations.

Future Trends and Emerging Concerns

  • Despite JN.1’s surge, EG.5 remains the most reported Variant of Interest (VOI) globally.
  • However, it has exhibited declining trends in recent weeks, signalling a dynamic landscape of emerging variants and the necessity for ongoing monitoring and analysis.


  • The emergence and dominance of omicron subvariant JN.1, characterized by the “FLip” mutation, pose potential challenges related to transmissibility, immune evasion, and vaccine efficacy.
  • Vigilant surveillance, robust research, and targeted interventions are crucial to mitigate the impact and better understand the evolving landscape of SARS-CoV-2 variants.


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