The World Health Organization has issued another regulation on the antigenic composition of COVID-19 vaccines. It maintains the priority use of monovalent vaccines for the JN.1 (JN.1 or KP.2) variant of the SARS-CoV-2 coronavirus, first recommended in April 2024 and confirmed in December of that year. This virus variant, with its characteristic L455S mutation, was first identified in August 2023 and quickly became dominant. The new regulation also, for the first time, approves monovalent vaccines for the LP.8.1 variant of the coronavirus as an acceptable alternative.
Ongoing monitoring of the antigenic composition of viruses and the immune response to infection and vaccination by the WHO Technical Advisory Group on COVID-19 Vaccine Composition (TAG-CO-VAC) indicates that the currently circulating virus variants originated from JN.1 and remain antigenically similar. Among these, the weekly proportion of LP.8.1 and LF.7 variants continues to increase, while the proportion of other variants under surveillance, such as KP.3, KP.3.1.1, XEC, and LB.1, is declining.
