There are many variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19). BA.2.86 was designated as a variant under monitoring by the World Health Organization on 17 August 2023. JN.1 (sometimes referred to as "Pirola"), a subvariant of BA.2.86 Omicron, emerged during August 2023 in Luxembourg. On 19 December 2023, JN.1 was declared by the WHO to be a variant of interest independently of its parent strain BA.2.86, but overall risk for public health was determined as low. Sars-cov-2 infects human respiratory epithelial cells through binding to human ACE2 receptors. Spike protein is a large type I transmembrane protein containing two subunits S1 and S2. S1 mainly contains a receptor binding domain (RBD), which is responsible for recognizing cell surface receptors. S2 contains the basic elements required for membrane fusion. S protein plays a key role in inducing neutralizing antibody and T cell responses as well as protective immunity.