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JN.1 - SARS-CoV-2 Variant

Viruses evolve.1 It’s the reason doctors recommend getting a flu shot annually.2

Viruses continuously evolve as a result of changes in their genetic code (caused for example by mutations). Some of these mutations result in changes to proteins on the surface of the virus.1,3 The COVID virus spike proteins attach themselves to human cells and cause infection – so it’s important for your body to be able to recognize them in order to train your immune system to fight off infection.4

As the virus responsible for COVID-19 changes or mutates, new variants emerge.1 Some of these variants may spread more easily, some are more resistant to previously developed vaccines.5 Your immune system may have trouble recognizing the new variants, increasing your risk of reinfection.6

JN.1 New SARS-CoV-2 Variant

During 2020, when COVID-19 was on the rise, the strain that caused the disease was known as the Wuhan strain.7 Over time, the virus that causes COVID then mutated to produce new strains, including the Alpha, Beta, Delta, Omicron variants and XBB subvariants.8 As of late spring, 2024, the primary strains circulating are JN1 and its descendants.8

JN.1 was first detected in the United Stated in September 2023.9 The JN.1 variant is a descendant of BA.2.86 that has the ability to transmit efficiently through additional mutations.10 

U.S. and EU public health authorities, as well as the World Health Organization, are updating their recommendations on what vaccines are needed to best combat and protect against COVID.11 These recommendations are based on extensive monitoring and data from public health institutions, industry and academia, and allow us to identify the COVID virus strain expected to cause the most infectious in the upcoming seasons.12 Vaccine manufacturers then prioritize and focus on towards this strain, producing and distributing updated vaccine doses that can help vaccine-induced immune responses to circulating COVID virus variants.12

  1. Markov, et al. Nat Rev Microbiol. 2023;21(6):361-379.
  2. CDC. How flu viruses can change: “drift” and “shift”. Available at: https://www.cdc.gov/flu/about/viruses/change.htm#print. [Accessed: August 2023].
  3. CDC. Science Brief: COVID-19 Vaccines and Vaccination. Available at: https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/fully-vaccinated-people.html. [Accessed: August 2023].
  4. CDC. Variants of the virus. Available at: https://www.cdc.gov/coronavirus/2019-ncov/variants/index.html. [Accessed: June 2024].
  5. CDC. SARS-CoV-2 Variant Classifications and Definitions. Available at: https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-classifications.html. [Accessed: August 2023].
  6. Antonelli M, et al. Risk factors and disease profile of post-vaccination SARS-CoV-2 infection in UK users of the COVID Symptom Study app: a prospective, community-based, nested, case-control study. Lancet Infect Dis. 2022;22(1):43-55.
  7. Wolf JM, et al. Molecular evolution of SARS-CoV-2 from December 2019 to August 2022. J Med Virol. 2023;95(1):e28366.
  8. CDC. COVID Data Tracker. Available at: https://covid.cdc.gov/covid-data-tracker/#variant-proportions. [Accessed: June 2024].
  9. Centers for Disease Control and Prevention. Update on SARS-CoV-2 Variant JN.1 Being Tracked by CDC. Available at: https://www.cdc.gov/ncird/whats-new/SARS-CoV-2-variant-JN.1.html [Accessed: March 2024]
  10. Johns Hopkins. What to Know About JN.1, the Latest Omicron Variant. Available at: https://publichealth.jhu.edu/2024/jn1-the-dominant-variant-in-the-covid-surge [Accessed: March 2024]
  11. WHO. XBB.1.5 updated risk assessment. Available at: https://www.who.int/docs/default-source/coronaviruse/20230620xbb.1.5.pdf?sfvrsn=fff6f686_3. [Accessed: August 2023].
  12. WHO. Statement on the antigen composition of COVID-19 vaccines. Available at: https://www.who.int/news/item/18-05-2023-statement-on-the-antigen-composition-of-covid-19-vaccines. [Accessed: August 2023].
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