About COVID-19 JN.1 Variant

Written by Dr HW, Joyce CHANG

The JN.1 variant is a sublineage of the coronavirus 19 (COVID 19) derived from the Omicron BA.2.86. It was first detected in mid-late 2023. The variant demonstrated a mutated L455S spike protein that helped evade immune response, allowing virus transmission to spread quickly.

In the US, the JN.1 variant went from making up <5% of COVID cases in mid-November 2023, to around 20% in December 2023; but by the third week of January 2024, it comprised over 85% of COVID cases.[1]

Coronavirus mutations develop rapidly and swiftly. According to the latest COVID-19 variant update by The U.S. Centers for Disease Control and Prevention in September 2024, the five most common lineages of COVID-19 are KP.3.1.1, KP.2.3, LB.1, KP.3 and KP.2 which constitute over 80% of the cases in the US.[2] All of these variants are derived from the JN.1 variant.

In virus neutralization assays, these JN.1 subvariants showed substantial resistance to the serum of individuals vaccinated with the XBB.1.5 COVID vaccine, i.e. individuals vaccinated with the XBB.1.5 COVID vaccine may not be immune to the latest JN.1 subvariants circulating in the community today. Though JN.1 appears to be more transmissible, the symptoms of an infection with the JN.1 variant do not appear to be more severe than other COVID variants.

The current and latest COVID vaccines available in the United States are mRNA vaccines and recombinant protein vaccines based on either the JN.1 variant or KP.2 (a JN.1 subtype). Starting from November 2024, the Government in Hong Kong will provide JN.1 vaccines to eligible persons aged 12 years and above under the Government COVID 19 Vaccination Programme, replacing the existing XBB COVID-19 vaccine. Comirnaty® Omicron JN.1 vaccination is available at Marina Medical now.

Who Should get COVID-19 JN.1 Vaccine?

The following groups are eligible for free booster doses six months after their last dose or COVID 19 infection (whichever later): older adults aged 50 and above, persons aged 18 to 49 with underlying comorbidities, persons with immunocompromising conditions aged 6 months and above, pregnant women and healthcare workers. For those not belonging to eligible groups, a booster dose of the JN.1 vaccine is available at a cost. For enquiries or to arrange vaccine booking, please contact us. 

[1] https://www.yalemedicine.org/news/jn1-coronavirus-variant-covid

[2] https://www.idsociety.org/covid-19-real-time-learning-network/diagnostics/covid-19-variant-update/#/+/0/publishedDate_na_dt/desc/

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