Unveiling the emergence of SARS-CoV-2 JN.1 sub-variant: Insights from the first cases at Charles Nicolle Hospital, Tunisia.

The JN.1 sub-variant is a new variant of the SARS-CoV-2 Omicron strain, derived from the BA.2.86 sub-variant. It was first detected in late 2023 and has quickly spread to many countries, becoming the most prevalent variant in some regions. JN.1 exhibits a unique mutation (L455S) in the spike protein compared to the BA.2.86 lineage, which may affect its transmissibility and immune evasion capabilities. JN.1 has been designated as a "variant of interest" by the World Health Organization due to its rapidly increasing spread and is being closely monitored for its impact on the COVID-19 pandemic. This study describes the emergence of SARS-CoV-2 JN.1 sub-variant in Tunisia, and reports its mutation profiles.Nasopharyngeal samples collected over a four-month period (October 2023 to January 2024) were subjected to RNA extraction and real-time RT-PCR confirmation of SARS-CoV-2 infection. The whole-genome sequencing was performed by an iSeq 100 sequencer and COVIDSeq kit reagents (Illumina, USA).Mutation analysis, using the NextClade platform and GISAID database, revealed the presence of JN.1 in 15 out of 80 positive cases (18.75%) during the study period.The emergence of JN.1 highlights the ongoing evolution of SARS-CoV-2 and the need for continued surveillance and research to better understand the characteristics and impact of emerging variants.