Key points:
- Vaccination remains an important public health countermeasure against COVID-19. As per the WHO Director General's standing recommendations for COVID-19 , Member States are recommended to continue to offer COVID-19 vaccination based on the recommendations of the WHO Strategic Advisory Group of Experts on Immunization (SAGE).
- SARS-CoV-2 continues to undergo sustained evolution since its emergence in humans, with important genetic and antigenic changes in the spike protein.
- The objective of an update to COVID-19 vaccine antigen composition is to enhance vaccine-induced immune responses to circulating SARS-CoV-2 variants.
- The WHO Technical Advisory Group on COVID-19 Vaccine Composition (TAG-CO-VAC) advises manufacturers that monovalent JN.1 or KP.2 vaccines remain appropriate vaccine antigens; monovalent LP.8.1 is a suitable alternative vaccine antigen.
- In accordance with WHO SAGE policy, vaccination should not be delayed in anticipation of access to vaccines with an updated composition.
The WHO Technical Advisory Group on COVID-19 Vaccine Composition (TAG-CO-VAC) continues to closely monitor the genetic and antigenic evolution of SARS-CoV-2 variants, immune responses to SARS-CoV-2 infection and COVID-19 vaccination, and the performance of COVID-19 vaccines against circulating variants. Based on these evaluations, WHO advises vaccine manufacturers and regulatory authorities on the implications for future updates to COVID-19 vaccine antigen composition. In April 2024, the TAG-CO-VAC recommended the use of a monovalent JN.1 lineage vaccine antigen as one approach to induce enhanced neutralizing antibody responses to JN.1 and its descendent lineages. In December 2024, the TAG-CO-VAC advised retaining the use of a monovalent JN.1 lineage vaccine antigen . Multiple manufacturers (using mRNA, recombinant protein-based, and adenovirus-vectored platforms) have updated COVID-19 vaccine antigen composition to monovalent JN.1 lineage formulations (JN.1 or KP.2). Several of these vaccines have been approved for use by regulatory authorities and introduced into vaccination programmes in some countries during the second half of 2024. Previous statements from the TAG-CO-VAC can be found on the WHO website .
The TAG-CO-VAC reconvened on 6-7 May 2025 to review the genetic and antigenic evolution of SARS-CoV-2; immune responses to SARS-CoV-2 infection and/or COVID-19 vaccination; the performance of currently approved vaccines against circulating SARS-CoV-2 variants; and the implications for COVID-19 vaccine antigen composition.
Evidence reviewed
The published and unpublished evidence reviewed by the TAG-CO-VAC included: (1) SARS-CoV-2 genetic evolution with additional support from the WHO Technical Advisory Group on SARS-CoV-2 Virus Evolution
