influenza vaccine

Advances in clinical immunogenicity evaluation of influenza vaccines.

Xu Nan N, Wang Liangliang L, Zhao Chunhui C, Shen Yanru Y et al.

Influenza vaccination is an effective intervention for preventing severe influenza, and assessing its immunogenicity is a critical step in determining vaccine protective efficacy. With the widespread use of influenza vaccines-including split-virion, subunit, recombinant protein, and live attenuated formulations-methods for evaluating immunogenicity have grown increasingly diverse and complex. This article systematically examines the advantages and limitations of various immunogenicity assessment approaches for influenza vaccines. It draws upon multidimensional evaluation frameworks covering humoral, cellular, and mucosal immunity, incorporating analytical techniques such as hemagglutination inhibition assays, microneutralization assays, enzyme-linked immunosorbent assays, mucosal secretory IgA detection, enzyme-linked immunospot assays, and flow cytometry. Furthermore, clinical challenge trials evaluations play an essential role in elucidating the relationship between immunogenicity and protective efficacy. This paper aims to establish a systematic and comprehensive reference framework for the development and immunogenicity evaluation of influenza vaccines, thereby advancing vaccine design and the prediction of protective outcomes toward greater precision.

Author Correction: GGCX promotes Eurasian avian-like H1N1 swine influenza virus adaption to interspecies receptor binding.

Zou Jiahui J, Jiang Meijun M, Xiao Rong R, Sun Huimin H et al.

Indirect comparison of mRNA-1010 versus enhanced influenza vaccines in adults aged 65 years and older during the 2024-2025 US influenza season.

Joshi Keya K, Situ Aaron A, Mehta Darshan D, Li Linwei L et al.

Seasonal influenza continues to cause severe disease among older adults in the United States despite enhanced vaccine recommendations, driven by immunosenescence and vaccine mismatch with circulating influenza viruses. mRNA-based influenza vaccines (mRNA-1010), addressing some of these challenges, have been developed for this population. A previous trial found mRNA-1010 demonstrated superior immunogenicity compared to enhanced high-dose influenza vaccination. As no direct evidence exists comparing mRNA-1010 efficacy to currently available enhanced influenza vaccines (EVs), we aimed to indirectly compare the effectiveness of mRNA-1010 and licensed EVs against medically attended influenza infection among adults ≥65 years in the US. We conducted an anchored indirect treatment comparison (ITC) using the Bucher method to estimate the relative vaccine effectiveness (rVE) of mRNA-1010 vs EV, with standard-dose egg-based influenza vaccine as the anchor, using individual patient-level data from adults ≥65 years from a real-world Optum claims-based analysis and the pivotal mRNA-1010-P304 clinical trial. Target trial emulation and inverse probability weighting (IPW) were implemented to address potential bias due to cross-population differences. Sensitivity analyses were conducted using alternative outcome definition, alternative weighting approaches and US trial sites only. Assessments of post-IPW supported a comparable common anchor for the ITC. Among adults ≥65 years, the indirect rVE of mRNA-1010 vs. enhanced vaccines against medically attended influenza was 12.82% (95% CI: -36.91%, 44.49%). Sensitivity analyses also supported these findings. mRNA-1010, a new mRNA-based influenza vaccine, was shown to be comparable to currently licensed EVs among older adults ≥65 years against medically attended influenza outcomes. Consistency of findings across sensitivity analyses support the robustness of these results. Newer influenza vaccine modalities, including mRNA-based vaccines provide an additional comparable option to existing EVs to help further reduce severe influenza disease burden among older adults ≥65 years for whom enhanced vaccines are recommended.

Vaccine-Preventable Diseases in Older Adults.

Al-Jabri Maha M, Rosero Christian C, Saade Elie A EA

Older adults are at an increased risk of vaccine-preventable diseases partly because of physiologic changes in the immune and other body systems related to age and/or accumulating comorbidities that increase the vulnerability to infections and decrease the response to vaccines. Strategies to improve the response to vaccines include using a higher antigenic dose (such as in the high-dose inactivated influenza vaccines) as well as adding adjuvants (such as MF59 in the adjuvanted inactivated influenza vaccine).