Monday, May 20, 2024

WHO Advises Transition to JN.1 Strain for COVID Vaccines

Amid ongoing efforts to adapt COVID-19 vaccines to emerging variants, the World Health Organization (WHO) Technical Advisory Group recommends a pivotal shift toward the JN.1 lineage for upcoming vaccine formulations.

WHO’s Technical Advisory Group on COVID-19 Vaccine Composition, convened semi-annually, recently advocated for incorporating the monovalent JN.1 strain into future vaccine iterations. This decision follows a comprehensive review of SARS-CoV-2’s genetic and antigenic evolution conducted in mid-April. Notably, the group highlighted the displacement of the XBB lineage by JN.1, anticipating that circulating variants will primarily derive from this lineage in the short term.

A year ago, the recommendation favored the XBB.1.5 strain. However, recent evidence from animal and human studies underscores the antigenic distinctiveness between XBB.1.5 and JN.1 variants. Studies reveal that neutralization titers against JN.1 are notably lower compared to XBB.1.5. Further complicating matters are mutations such as FLiRT (F for L at position 456 and R for T at position 346), observed in JN.1 variants like KP.2, potentially impacting vaccine efficacy.

Experts caution that while existing vaccines may offer some protection against JN.1, continued viral evolution may compromise their effectiveness. Nevertheless, preliminary findings from human immunogenicity studies of a monovalent JN.1 vaccine exhibit promising results, indicating heightened neutralization against co-circulating variants.

Acknowledging the limitations of their analysis, including insufficient genetic surveillance and predictive challenges posed by emerging mutations, WHO urges countries to maintain vaccination drives with existing emergency-listed or prequalified vaccines. Meanwhile, the US FDA’s Vaccines and Related Biological Products Advisory Committee is set to convene in mid-May to deliberate on strain-selection recommendations for the upcoming vaccine cycle, emphasizing the global effort to stay ahead of the virus’s evolution.

Related Articles

Latest Articles

Most Popular