JN.1 variant has clinical features similar to previous Covid-19 variants: Study

A first-of-its-kind study conducted by experts from B J Medical College (BJMC) and ICMR National Institute of Virology (NIV) has found that JN.1, the dominant Covid-19 variant in India, has clinical features similar to previous circulating variants in Maharashtra without increased severity.

The study titled ‘Appearance and prevalence of JN.1 SARS-CoV-2 variant in India and its clinical profile in the state of Maharashtra’ was published in the medical journal ‘Cureus of Springer Nature Group’ on March 22.

The research team included: Dr Rajesh P Karyakarte, head of the microbiology department, B J Medical College; Dr Varsha Potdar, scientist and infectious disease expert, ICMR-NIV; and Dr Rashmita Das, Dr Mansi V Rajmane, Dr Sonali Dudhate, Dr Jeanne Agarasen, Dr Praveena Pillai, Dr Priyanka M Chandankhede, Dr Rutika S Labhshetwar, Dr Yogita Gadiyal, Dr Preeti P Kulkarni, Dr Safanah Nizarudeen, Dr Sushma Yanamandra, Dr Nyabom Taji and Dr Suvarna Joshi from BJMC.

In August 2023, the BA.2.86 SARS-CoV-2 variant, with over 30 spike protein mutations, emerged amidst the global dominance of XBB sub-lineages. It evolved into JN.1 by late 2023, spreading across 71 countries. JN.1, distinct for its L455S mutation, significantly dominated global sequences, raising concerns over its transmission and clinical impact. This study investigates JN.1’s clinical severity and its effect on hospital admissions in Maharashtra. It includes the 3,150 curated Indian SARS-CoV-2 whole genome sequences collected between August 1, 2023 and January 15, 2024. Lineage and phylogenetic analysis of the sequences was performed using Nextclade. Interviews were conducted to confirm the demographic details and obtain clinical information on JN.1 and its sub-lineages.

In Maharashtra, the JN.1 variant was first identified on November 23, 2023. A total of 279 JN.1 cases were included in the clinical study. Of these, 95.34% (266/279) had symptomatic disease with mild symptoms; cold (187/279, 67.03%) being the most common symptom, followed by fever (156/279, 55.91%), cough (114/279, 40.86%) and headache (28/279, 15.64%).

Furthermore, of all the cases, 13.26% (37/279) required institutional quarantine or hospitalisation, and the rest of the patients were isolated at home. Among the hospitalised patients, 54.05% (20/37) cases were given conservative treatment while 45.95% (17/37) cases required supplemental oxygen therapy, as per the study.

According to doctors, as many as 94.26% (263/279) cases received at least one dose of the Covid-19 vaccine while 5.02% (14/279) were not vaccinated, of which, most were children aged zero to nine years (5/14, 35.71%). The overall recovery rate among JN.1 cases was 98.57% (275/279) with 1.43% (4/279) cases succumbing to the infection, they said.

Out of the total 3,150 sequences included in the study, 144 different lineages were identified following Nextclade Pangolin nomenclature. JN.1 was the most common lineage (75.46%), followed by XBB.2.3 (8.92%) and XBB.1.16 (5.94%).

The JN.1 variant reportedly grew from 8.33% since its first detection in the 40th week, 2023 to 93.83% in week two, 2024. Of all the sequences submitted by various states, 75% were of the JN.1 variant, with the highest proportion of JN.1 sequences originating from Maharashtra (26.42%), followed by West Bengal (13.46%), Andhra Pradesh (12.33%), Kerala (12.12%) and Karnataka (11.99%).

Dr Karyakarte, said, “This is the first-of-its-kind study conducted globally and the JN.1 variant was found to have emerged as the predominant SARS-CoV-2 variant in India, with clinical presentation similar to previous variants circulating in Maharashtra and India. JN.1 has not been associated with severe disease outcomes; its enhanced transmissibility underscores the importance of studying the ongoing viral evolution.”

“The evolution of the virus by adding novel mutations necessitates prompt detection strategies to prevent potential surges. The pressing necessity for swift identification and the clinical features of new variants will enable public health authorities to predict and mitigate the risks effectively, ensuring preparedness against future outbreaks,” Dr Karyakarte said.