Influenza B Vaccines: Current Landscape and Novel Development Strategies

Influenza B virus (IBV) represents a significant global health threat, contributing 20-30% of annual influenza cases and causing substantial morbidity and mortality across all age groups. Current seasonal vaccines demonstrate variable effectiveness, highlighting the urgent need for next-generation approaches that provide enhanced and sustained protection against both IBV lineages. Moreover, continuous antigenic drift of circulating viruses progressively reduces the match between vaccine-induced antibodies and contemporary strains, necessitating broad-spectrum protection strategies. This review discusses influenza B virus control strategies, encompassing both conventional approaches and emerging vaccine technologies. While antiviral therapy, epidemiological surveillance, diagnostics, and non-pharmaceutical public-health measures are integral components of influenza B control, the present review focuses specifically on vaccine-based strategies. By critically appraising the available evidence, this review evaluates the extent to which these strategies may improve the effectiveness of IBV vaccines and, in the longer term, inform the prospect of reducing the burden of-or potentially eliminating-influenza B virus, a goal that remains hypothetical and requires clinical validation.