influenza vaccine (egg-based) (Teratect)

An investigation into post-pandemic ethnic group and deprivation inequalities in influenza and COVID-19 hospitalizations.

Scott Meg M, Browning Lucy L, Roberts Tirion T, De Boer Jessica J et al.

Health system decision-makers need evidence on how modifiable factors contribute to inequalities to inform effective interventions. We examined ethnic group and deprivation inequalities in influenza and COVID-19 hospitalizations in England (2023-2024) among vaccine-eligible individuals, using causal mediation analysis to assess the roles of deprivation, vaccination uptake and comorbidities. For influenza, hospitalization odds were highest among Pakistani and Bangladeshi groups, compared with White British individuals. Deprivation mediated 26% of the total ethnic group effect for the Pakistani group and 41% for the Bangladeshi group, whilst comorbidities contributed little. Ethnic group differences in COVID-19 hospitalizations were minimal in this post-pandemic period. For both infections, the most deprived group had disproportionately high hospitalization compared to the least deprived. For influenza, vaccination uptake mediated 17%-26% of deprivation effects, whilst for COVID-19, there were no meaningful residual deprivation inequalities after including vaccination uptake and comorbidities. Vaccination uptake and deprivation mediate a substantial proportion of inequalities in hospitalization for influenza and COVID-19 in the vaccine-eligible cohort. Improving vaccination coverage in under-vaccinated groups should remain a public health priority.

Extended dosing intervals enhance the durability of a self-amplifying mRNA vaccine against pandemic H5N1 influenza: a randomized, observer-blind, dose-finding Phase I study.

Pragalos Antoinette A AA, Pacciarini Filippo F, Jin Hongfan H, Hopkins Terri T et al.

Avian influenza poses a persistent pandemic threat, yet traditional vaccines face production delays. Self-amplifying mRNA (sa-mRNA) technology offers potential advantages, including rapid development, dose sparing, and enhanced, durable immunity. We evaluated ARCT-2304, a bicistronic sa-mRNA vaccine encoding H5N1 hemagglutinin (HA) and neuraminidase (NA), in a Phase 1 randomized, observer-blind trial (NCT06602531). Healthy adults (N = 212) received two doses of ARCT-2304 (1.5, 5, or 12 mcg) or control/placebo on a 4- or 8-week schedule. Primary outcomes evaluated safety and reactogenicity (solicited/unsolicited/serious adverse events [AEs]) and immunogenicity (HA inhibition and NA enzyme-linked lectin assays 28 days post-second dose). Immunogenicity results were benchmarked using serum from a prior study supporting licensure of an H5N1 vaccine. ARCT-2304 was well-tolerated, displaying mostly mild-to-moderate, transient, dose-dependent solicited AEs, with no safety concerns identified. Two doses elicited robust HA and NA humoral responses. An 8-week interval yielded higher magnitude and greater durability than a 4-week schedule, with neutralizing and anti-NA antibodies remaining significantly elevated 6-7 months post-second dose. ARCT-2304 also induced dose-dependent, Th1-polarized T-cell responses peaking at Day 29. These findings support advancing sa-mRNA platforms for pandemic influenza preparedness.

Reoviridae-derived short trimerization domain for stabilizing homo-trimerization of vaccine immunogens and therapeutic proteins.

Wei Min M, Bu Qingfang Q, Xiao Jin J, Yuan Lunzhi L et al.

Trimerization motifs play pivotal roles in structural biology and therapeutic protein engineering. Here, we describe a short trimerization motif (rFd1303) derived from the Reoviridae family reovirus σ1 protein. Compared with the widely used T4-Foldon, the rFd1303 increased recombinant protein yields. The rFd1303-fused immunogens of SARS-CoV-2 spike and influenza hemagglutinin elicited antibody responses comparable to T4-Foldon-fused controls in mice. Using this tag, we engineered a trimeric ACE2-Ig fusion protein (TriACE2-Ig) that remained stable after 30 days at room temperature and neutralized a broad range of ACE2-utilizing sarbecoviruses, including 19 SARS-CoV-2 variants, SARS-CoV, and pangolin coronaviruses GD and GX, with higher potency than monomeric ACE2-Ig. In the hamster model challenged with various SARS-CoV-2 variants, our data demonstrated that intranasal TriACE2-Ig administration markedly reduced viral loads, virus-induced body-weight loss, lung pathology, and decreased within-cage virus transmission. These findings highlight rFd1303 as a versatile trimerization platform for vaccine and therapeutic protein development.

First mRNA Cancer Vaccine Succeeds in Phase III Trial.

Adding the mRNA-based individualized neoantigen vaccine intismeran autogene to the PD-1 inhibitor pembrolizumab following surgery for melanoma reduced the risk of disease recurrence or death by 42%, according to the results of the phase III INTerpath-0001 trial. The data were presented at the ESMO Congress 2026, held October 23-27, in Madrid, Spain.