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influenza virus vaccine (FluShield)

✓ Approved

Pfizer, Inc. · Vaccine · Vaccine

What is influenza virus vaccine?

influenza virus vaccine is a vaccine developed by Pfizer, Inc.. It is approved for therapeutic indications via injectable (others) or intramuscular (im) injection.

Drug Profile

Brand NamesFluShield
CompanyPfizer, Inc.
Drug ClassVaccine, Large Molecules
RouteInjectable (Others), Intramuscular (IM) Injection
StatusApproved
Sources: ClinicalTrials.gov, Pfizer, Inc.

Related Research Articles

PubMedFrontiers in microbiology2026-09-19

Epidemiological characteristics and genetic evolution of rhinovirus in Jining City, 2024-2025.

Zhao Mingsheng M, Song Tongyun T, Li Wen W, Jiang Yajuan Y et al.

To investigate the epidemiological characteristics and genetic evolution of rhinovirus (RV) among patients with influenza-like illness (ILI) in Jining City, Shandong Province, from 2024 to 2025, and to provide scientific evidence for the formulation of regional respiratory virus prevention and control strategies. A total of 2,724 throat swab specimens were collected from ILI cases at Jining First People's Hospital between 2024 and 2025. Ten respiratory viruses were screened using real-time reverse transcription-quantitative PCR. Of 101 RV-positive specimens, 30 with lower cycle threshold (Ct) values were subjected to whole-genome targeted enrichment sequencing. Molecular typing was performed based on VP1 region nucleotide sequences. A maximum likelihood (ML) phylogenetic tree was constructed, and genetic distances and key amino acid substitution sites were analyzed. Among the 2,724 specimens, influenza virus had the highest detection rate (14.98%), followed by SARS-CoV-2 (7.05%), with rhinovirus ranking third (3.71%, 101/2,724). The RV-positive rate in 2025 (5.53%) was significantly higher than in 2024 (1.95%; χ2 = 23.55, P < 0.001). An unusually high RV positivity rate (23.53%) was observed in November 2025. The 30 sequenced strains were classified into RV-A (73.33%, 17 genotypes), RV-B (10.00%, 3 genotypes), and RV-C (16.67%, 3 genotypes), with RV-A as the predominant species and genotypes exhibiting high diversity. Phylogenetic analysis revealed co-circulation of multiple species and genotypes, with 2025 strains distributed across a broader range of the phylogenetic tree. The nucleotide similarity between the VP1 regions of the 30 strains and their respective reference strains ranged from 86.08% to 95.37%, and amino acid similarity from 91.58% to 99.65%, with 1-24 amino acid substitution sites per strain. RV-A was the predominant rhinovirus species circulating in Jining City during 2024-2025, with high genotypic diversity. The detection rate in 2025 increased significantly compared with 2024, accompanied by an autumn epidemic peak. Rhinoviruses in this region exhibit ongoing evolution in the VP1 region. Enhanced molecular surveillance is warranted to dynamically monitor epidemiological and evolutionary trends.

PMID 42761029
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PubMedBMC immunology2026-09-19

Association between body mass index and influenza antibody titer and immune cell count after influenza vaccination: an exploratory study.

Böll Selina S, Schmitz Timo T, Eggers Maren M, Linseisen Jakob J et al.

Obesity is associated with altered immune function and may therefore influence the response to influenza vaccination. So, the objective was to investigate whether body mass index (BMI) affected influenza-specific antibody titers and immune cell counts after vaccination. A subgroup of 25 participants from the MEGA cohort, a prospective observational study in Augsburg, Germany, aged 25-65 years, was analyzed, including 18 normal-weight individuals and 7 participants with obesity. Influenza antibody titers and immune cell phenotypes were assessed at four visits over nine months following vaccination. Differences between normal-weight and obese individuals were analyzed graphically using boxplots and tested using the Wilcoxon signed-rank test and the Mann-Whitney-U-test. At baseline, no significant differences in antibody titers were observed between BMI groups. Following vaccination, antibody titers increased in both groups and remained above pre-vaccination levels throughout follow-up. In the normal-weight group, the titers for all four analyzed antibodies differed significantly at every visit compared to visit 1. This was not the case in the obese group, where only the titers for the antibodies B/Colorado/06/2017 and B/Phuket/3073/2013 differed at the different visits in comparison to visit 1. Furthermore, obese participants showed a non-significant downward trend in Treg cell proportions over time; total T-cell counts did not demonstrate clear group-specific differences. B-cell proportions showed no consistent time trend, but significant within-group differences were observed between visits 1 and 4 in the normal-weight group and visits 1 and 2 in the obese group, with significant differences between groups at visits 1 and 3. The findings suggest that BMI may influence cellular immune responses after influenza vaccination, whereas antibody responses appeared broadly similar among BMI groups. Given the limited sample size these observations should be interpreted as exploratory. Larger studies are needed to clarify this relationship and to inform the development of tailored vaccination strategies for obese individuals.

PMID 42760530
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PubMedAAPS PharmSciTech2026-09-19

Comprehensive Stability Assessment of Squalene in a Nanoemulsion Adjuvant and the SpiN-Tec Vaccine: HPLC Quantification, Stress Testing, and Stability Studies.

Gomes Isabela Pereira IP, Rivelli Graziella Gomes GG, Bagno Flávia Fonseca FF, Hojo-Souza Natália Satchiko NS et al.

Squalene-based nanoemulsions are widely used as adjuvants in vaccine formulations, but their stability can be affected by environmental factors such as pH, oxidative stress, temperature, and light. We have produced a squalene nanoemulsion (CTVad1) to support the clinical development of new vaccines. This study aimed to develop and validate an HPLC method for squalene quantification in SpiN-Tec, a recombinant protein vaccine against COVID-19. We also aimed to evaluate the stability of the CTVad1 adjuvant and SpiN-Tec under controlled storage conditions. A reversed-phase HPLC method was developed and validated, and comprehensive forced degradation studies were performed on the raw material and SpiN-Tec under acidic, basic, oxidative, thermal, and photolytic conditions to demonstrate the stability-indicating capability of the method. Physicochemical, morphological, and biological characteristics were assessed, and stability studies of both the vaccine and the CTVad1 adjuvant were performed under accelerated and long-term conditions. The HPLC method was selective, precise, accurate, linear, and robust. Squalene raw material degraded under all tested conditions, whereas formulation in nano-sized globules improved its stability, with degradation observed only under hydrogen peroxide and light exposure. CTVad1 remained stable over time, exhibiting only minor, non-critical changes within the specification limits in both accelerated and long-term stability studies, regardless of the glass packaging used (clear or amber). In addition, the SpiN-Tec vaccine maintained its physicochemical and biological integrity under all tested conditions, with all evaluated parameters remaining within the established specification ranges. Our findings demonstrate that proper formulation, packaging, and storage conditions can preserve squalene stability in nanoemulsion-based vaccines, ensuring the quality, safety, and efficacy of the SpiN-Tec vaccine and its adjuvant throughout shelf life.

PMID 42760453
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PubMedOcular immunology and inflammation2026-09-19

Bilateral Maculopathy in an Infant Following Measles, Mumps, Rubella, and Varicella-Zoster (MMRV) Vaccination.

Ben-Avi Ravid R, Amer Radgonde R

To report on the long-term clinical outcome of a healthy infant who presented with posterior uveitis following the administration of the combined measles, mumps, rubella, and varicella (MMRV) vaccine. Descriptive case report. A 13-month-old infant presented with bilateral visual loss two weeks after receiving the MMRV vaccine. Ophthalmic examination revealed bilateral retinitis and retinal vasculitis with exudative retinal detachment. Extensive infectious work-up was conducted including serologic exams and PCR testing of blood, aqueous humor, cerebrospinal fluid and urine. Serological tests for measles yielded positive IgM and IgG titers. PCR testing for measles in the aqueous humor and urine was negative. Neurologic assessment and neuroimaging were unremarkable, excluding central nervous system involvement. Empiric systemic antiviral and corticosteroid therapy was initiated. Gradual resolution of posterior uveitis ensued, culminating in bilateral macular scars. Over a six-year follow-up period, the patient demonstrated stable ocular findings with no evidence of recurrent inflammation or systemic autoimmune disease. Final visual acuity was 6/9 in each eye. This case represents a rare occurrence of non-necrotizing retinitis following MMRV vaccination. To our knowledge, this is the first report describing the sequential OCT characteristics of presumed measles vaccine-associated retinitis. The prolonged follow-up period supports the absence of an alternative etiology and provides valuable insight into the long-term course and visual prognosis of vaccine-associated retinopathy.

PMID 42760840
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PubMedCell proliferation2026-09-19

Olfactory Tuft Cells Are Critical to Basal Inflammation, Innate Immune Response to Viral Infection, and Modulation of Quiescent Stem Cell Activation, Proliferation and Differentiation.

Zhang Sai-Sai SS, Wang Haiyan H, Yang Yi-Sen YS, Li Yi-Hong YH et al.

The olfactory mucosa serves as both a sensory organ and an immune barrier to protect against bacterial and viral invasion and other insults. It is unclear how different types of olfactory mucosal cells coordinate and contribute to these two functions. We set out to reveal the critical roles of a subset of microvillous cells of the mucosa, olfactory tuft cells, in protecting and reconstructing this vital olfactory sensory organ. We first validated the expression of canonical gustatory signalling proteins and other molecular markers in olfactory tuft cells. Genetic disruption of the Gng13 and Trpm5 genes that encode the two gustatory signalling proteins, G protein subunit Gγ13 and transient receptor potential ion channel Trpm5, respectively, resulted in elevated basal inflammation and enhanced activation of the quiescent stem cells-horizontal basal cells (HBCs) in the mucosa. Nasal infection of H1N1 influenza virus further exacerbated the inflammation and delayed the resolution of inflammation in the mutant mucosa, including more immune cell infiltration, augmented cytokine production and cell death, increased HBC proliferation and direct differentiation into tuft cells, and prolonged olfactory tuft cell hyperplasia. Cytokine treatment of the cultured olfactory epithelial organoids indicated that the cytokines that were found to be elevated in the mutant mucosa, including interleukin-4 (IL-4), IL-13 and interferon-γ (INF-γ), are able to stimulate HBC activation. Together, our results indicate that olfactory tuft cells play an important role in maintaining the baseline inflammation under the steady-state condition, and altering inflammatory magnitude and modulating HBC activation and differentiation in the olfactory mucosa following the viral infection. Our findings shed light on new roles of olfactory tuft cells in innate immune response, quiescent stem cell activation and neuroimmune interactions, and provide novel therapeutic targets for preventing and treating stem cell-related olfactory disorders such as chronic rhinosinusitis and long COVID.

PMID 42760864
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PubMedBMC genomics2026-09-19

Divergent host adaptation in Marburg virus: a hypothesis-generating framework for prioritizing non-traditional reservoirs.

Chen Qi Q, Hu Jingjing J, Hu Siru S, Wang Yuxi Y et al.

Although Rousettus aegyptiacus is the primary natural reservoir of Marburg virus (MARV), recent atypical outbreaks and viral genomic diversification suggest a highly complex host-pathogen ecology. Here, we systematically evaluated the molecular homologies between MARV and diverse mammalian taxa to identify putative reservoir hosts and guide targeted surveillance. A multi-dimensional molecular characterization of the Marburg virus (MARV) genome was performed using an integrative suite of computational approaches. Distant sequence homology was interrogated via BLAST in conjunction with a null model framework, supplemented by granular analyses of codon usage bias, nucleotide composition, and dinucleotide frequencies. For comparative genomic context, we evaluated a cohort of 63 mammalian species across the orders Rodentia, Primates, Chiroptera, and Perissodactyla. Multidimensional molecular profiling showed varied genomic similarity between MARV and mammalian groups, with stable convergence observed in Perissodactyla and certain rodents across multiple codon usage indices. Notably, the effective number of codons (ENC) in Equus caballus (52.43) nearly matched MARV (52.44), and Equus asinus exhibited the lowest average RSCU Manhattan distance to the virus (0.25). Additionally, MARV's CpG suppression ([Formula: see text] = 0.48) was consistent with the CpG depletion levels characteristic of the studied mammalian taxa. Through the lens of computational biology, this study identifies putative host cohorts within the orders Perissodactyla and Rodentia that share distinct genomic, codon-usage, and dinucleotide-frequency homologies with MARV. These findings establish high-priority targets for downstream ecological field monitoring, seroepidemiological surveys, and experimental validation, ultimately providing a scientific blueprint to refine zoonotic surveillance networks under the global 'One Health' paradigm.

PMID 42760518
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