In a recent study posted to the bioRxiv preprint* server, researchers in Japan evaluated the virological characteristics of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) KP.3.1.

1 variant. SARS-CoV-2 BA.2.

86.1.1, viz .

, the JN.1 variant, has outpaced XBB lineages by the start of 2024. It emerged from the BA.

2.86.1 variant with an L455S substitution within the spike protein .

The sub-variants of JN.1, such as KP.2 and KP.

3, have emerged over time; these sub-variants harbor R346T, F456L, and Q493E substitutions in the spike. In addition, JN.1 sub-variants, such as LB.

1, KP.2.3, and KP.

3.1.1, which acquired a serine deletion in the spike, have been spreading since June 2024.

Previously, the authors characterized the features of SARS-CoV-2 LB.1, KP.2, KP.

2.3, and KP.3 variants.

Study: Virological characteristics of the SARS-CoV-2 KP.3.1.

1 variant . Image Credit: Fit Ztudio / Shutterstock *Important notice: bioRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information. The study and findings In the present study, researchers investigated the characteristics of SARS-CoV-2 KP.

3.1.1.

First, they used a Bayesian multinomial logistic model to estimate the variant’s relative effective reproduction number (R e ) based on surveillance data from the United Kingdom (UK), the United States (US), Canada, Spain, and Franc.