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influenza vaccine

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Sinovac Biotech · Vaccine · Vaccine

What is influenza vaccine?

influenza vaccine is a vaccine developed by Sinovac Biotech. It is approved for therapeutic indications via injectable (others).

Drug Profile

CompanySinovac Biotech
Drug ClassVaccine, Large Molecules
RouteInjectable (Others)
StatusApproved
Sources: ClinicalTrials.gov, Sinovac Biotech

Related Research Articles

PubMedThe Journal of infectious diseases2026-07-17

Influenza Antibody Levels Associated with Laboratory-Confirmed Influenza in a Test-Negative Study Design, US Flu VE Network, November 2018-May 2019.

Flannery Brendan B, Chung Jessie R JR, Holiday Crystal C, Jefferson Stacie S et al.

We assessed associations between antibody concentrations within 7 days of symptom onset and testing positive for influenza virus infection among outpatients enrolled in a test-negative study. From November 2018─May 2019, study sites in five states obtained serum and respiratory specimens from outpatients aged ≥18 years presenting with acute respiratory illness. Respiratory specimens were tested for influenza virus, and viral clades were identified by genomic sequencing. We measured influenza antibody titers against vaccine and circulating viruses by hemagglutination inhibition (HI), microneutralization (MN) and neuraminidase inhibition (NAI) assays. Reduction in odds of influenza-associated illness at increasing HI, MN and NAI antibody titers was estimated using logistic regression adjusting for influenza vaccination status and time since beginning of influenza season. Among 175 patients with confirmed influenza virus infection, including 112 with influenza A(H1N1)pdm09 and 63 with A(H3N2) (44 clade 3C.3a), and 130 test-negative control patients, higher HI, MN and NAI antibody titers against circulating influenza viruses were associated with lower odds of confirmed influenza. Odds of A(H1N1)pdm09 infection were 44% and 54% lower for each two-fold increase in A(H1N1)pdm09 HI or NAI titer, respectively. Odds of A(H3N2) infection were 49% and 28% lower, respectively, for each two-fold increase in MN or NAI titer against circulating A(H3N2) virus clade. NAI titers were independently associated with lower odds of influenza A(H1N1)pdm09 and A(H3N2) after controlling for HI titer. Higher influenza antibody titers against circulating viruses were associated with lower likelihood of influenza virus infection among adult patients with acute respiratory illness.

PMID 42463137
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PubMedVirologica Sinica2026-07-17

Pygenic Acid A, a Small-Molecule PD-1/SHP-2 Inhibitor, Enhances Efficacy of Therapeutic Melanoma Vaccines and Prophylactic Influenza Vaccines.

Yan Yan Y, Li Yitong Y, Mei Wenyi W, Li Yixin Y et al.

Overcoming immunosuppressive tumor microenvironments remains a critical challenge in advanced vaccine development. Here, we evaluated Pygenic acid A (PA), an intracellular small-molecule inhibitor targeting the PD-1/SHP-2 axis, as a novel vaccine adjuvant. The adjuvant efficacy of PA was systematically assessed in two murine models: a therapeutic B16-F10 melanoma lung metastasis model and a prophylactic lethal H1N1 influenza virus challenge model. In the melanoma metastasis model, PA potentiated the anti-tumor effect of the mTRP2 vaccine, markedly inhibiting pulmonary metastatic lesions and prolonging the survival of tumor-bearing mice. Mechanistically, PA robustly boosted the intratumoral infiltration of functional T cells, thereby reversing local tumor immunosuppression. In the influenza vaccination model, consistent immunostimulatory effects were observed: the PA-adjuvanted hemagglutinin (HA) vaccine effectively elicited broad-spectrum cross-neutralizing antibody responses and provided complete protection against lethal heterologous influenza virus challenge. Further mechanistic investigations demonstrated that PA specifically promoted the differentiation of T follicular helper (Tfh) cells and the expansion of germinal center (GC) B cells in draining lymph nodes, while triggering a robust Th1-type cellular immune response dominated by IFN-γ secretion. Furthermore, in vivo safety assessments verified that PA intervention induced no obvious systemic inflammation, hematological abnormalities, or visceral organ injury, indicating a favorable safety profile. Collectively, these results demonstrate that PA serves as a potent and safe intracellular checkpoint-targeting adjuvant capable of potentiating both cellular immunity and cross-protective humoral immunity, holding great translational promise for the development of advanced cancer vaccines and broad-spectrum influenza vaccines.

PMID 42462877
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PubMedmedRxiv : the preprint server for health sciences2026-07-17

Post-vaccination expansion of extrafollicular Th10 and regulatory Tfr cells distinguishes strong from weak influenza vaccine responses in older adults.

Mahajan Avinash S AS, Ravichandran Sathyabaarathi S, Marches Radu R, Yazici Yilmaz Yucehan YY et al.

Despite the superior efficacy of high-dose influenza vaccines, over one-third of older adults fail to respond. Yet, the mechanisms underlying this impaired vaccine responsiveness remain poorly understood. Here, we performed longitudinal profiling of older adults (n=60) receiving high-dose influenza vaccination to identify immune programs associated with vaccine responsiveness. Strong responders exhibited a primed baseline immune state characterized by elevated plasma cytokines and chemokines, followed by enhanced IFN-γ responses and coordinated transcriptional and epigenetic activation of cDC2 cells at day 1. By day 7, CD4⁺ T-cell trajectories diverged: strong responders preferentially expanded influenza-specific activated cTfh1 ( CXCR5 + CXCR3 + ICOS + CD38 + ) and influenza-specific Th10 ( CXCR5⁻ CXCR3 + PD1 + IL10⁺ ) cells, whereas weak responders expanded regulatory cTfr ( CXCR5⁺ FOXP3⁺ ) cells. Th10 expansion correlated with plasmablast and antibody responses and was independently validated in a larger influenza vaccination cohort, including younger adults. Functionally, Th10 cells promoted memory B-cell differentiation into plasmablasts and production of influenza-specific IgGs. TCR analyses revealed minimal clonal overlap between Th10 and cTfh1 cells. Together, these findings identify divergent helper and regulatory CD4⁺ T cell programs associated with vaccine responsiveness and establish Th10 cells as a previously unrecognized component of vaccine-induced humoral immunity.

PMID 42465941
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PubMedIndian journal of medical microbiology2026-07-17

The Resurgence of Respiratory Viruses After COVID-19: Molecular Insights from Pediatric SARI in Kashmir.

Wani Sanam Rasool SR, Fomda Bashir Ahmad BA, Bhat Mushtaq Ahmad MA, Bashir Gulnaz G et al.

Respiratory viruses are major contributors to severe acute respiratory infections (SARI) in children. Data on their molecular epidemiology in northern India remains limited, particularly in the post-COVID-19 period. This study aimed to determine the prevalence and distribution of respiratory viral pathogens among hospitalized pediatric SARI patients in Kashmir. A prospective study was conducted from October 2023 to April 2025 at Sher-i-Kashmir Institute of Medical Sciences, Srinagar. Children aged ≤15 years meeting the World Health Organization SARI case definition were enrolled. Nasopharyngeal and/or oropharyngeal samples were collected and tested using real-time polymerase chain reaction assays for SARS-CoV-2, Influenza A and B, Respiratory Syncytial virus (RSV) A and B, Adenovirus, Human metapneumovirus, Rhinovirus, and Para-influenza viruses. A total of 326 pediatric SARI cases were included. At least one respiratory virus was detected in 200 patients (61.3%). RSV was the most frequently detected virus, with RSV-B identified in 111 cases (34.0%) and RSV-A in 26 cases (7.9%). Influenza viruses accounted for a smaller proportion, including influenza A(H1N1) in 12 cases (3.6%), influenza A(H3N2) in 6 cases (1.8%), and influenza B (Victoria lineage) in 21 cases (6.4%). Other viruses detected included Adenovirus, Para-influenza virus, Rhinovirus, and Human metapneumovirus. Most infections occurred during winter months and predominantly affected infants. Respiratory viruses account for a substantial proportion of pediatric SARI cases in Kashmir, with RSV emerging as the predominant pathogen in the post-pandemic period. Strengthening molecular surveillance may improve diagnostic stewardship and guide targeted prevention strategies.

PMID 42462876
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PubMedMicrobiology spectrum2026-07-17

Cellular tropism of highly pathogenic avian influenza (HPAI) A(H5N1) clade 2.3.4.4b viruses in human respiratory and bovine mammary epithelial cells.

Brock Nicole N, Zeng Hui H, Pappas Claudia C, Kieran Troy J TJ et al.

The recent introduction and spread of HPAI A(H5N1) clade 2.3.4.4b viruses to U.S. dairy cattle demonstrate their ability to adapt to new mammalian hosts. Although multiple A(H5N1) genotypes have caused human infections, only two clade 2.3.4.4b genotypes (B3.13 and D1.1) have been detected in cattle, suggesting clade- or genotype-specific tropism. Understanding how these viruses replicate in human airway and bovine mammary epithelial cells is important for assessing viral evolution, mammalian adaptation, and associated public health risks. Here, we characterized replication kinetics and immune gene expression in human bronchial epithelial (Calu-3) cells and bovine mammary epithelial (MAC-T) cells infected with A(H5N1) clade 2.3.4.4b human isolates representing the B3.13, D1.1, and B3.2 genotypes, an A(H5N1) clade 1 virus, and an A(H1N1)pdm09 strain. All viruses replicated efficiently in Calu-3 cells, although replication was delayed at 33°C compared to 37°C. Clade 2.3.4.4b viruses induced moderate expression of type I interferon and proinflammatory response in Calu-3 cells, but at lower levels than the A(H1N1)pdm09 and A(H5N1) clade 1 strains. Replication and immune activation varied markedly among clade 2.3.4.4b genotypes in MAC-T cells. B3.13 viruses achieved higher titers and triggered stronger induction of innate immune response genes than other A(H5N1) genotypes or clades. These findings indicate genotype- and cell type-specific differences in replication and host responses, with B3.13 showing enhanced tropism in bovine mammary cells, consistent with adaptation that may elevate zoonotic risk. Our results highlight the value of comparative studies across host cell types and diverse viral isolates to inform risk assessments for emerging influenza viruses. Influenza A viruses cross species barriers through a combination of factors, including the ability to bind to and infect permissive cells, replicate efficiently, and modulate host immune responses. Since 2024, A(H5N1) clade 2.3.4.4b viruses have continued to evolve, infecting a broad range of avian and mammalian species, including cattle in the United States, and causing sporadic human infections. Here, we evaluated a panel of A(H5N1) clade 2.3.4.4b viruses isolated from humans to assess their replication and host responses in two relevant mammalian cell types: human bronchial epithelial cells and bovine mammary gland epithelial cells. While all genotypes replicated efficiently in human bronchial epithelial cells, only B3.13 viruses showed strong replication and broad host response induction in bovine mammary epithelial cells. These results underscore variation in evolution, tissue tropism, and host adaptation among A(H5N1) clade 2.3.4.4b viruses and highlight the need for continued surveillance and close monitoring of B3.13 genotype viruses.

PMID 42466872
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PubMedVaccine2026-07-17

Quality improvement programs for adult immunization: a scoping literature review.

Dudley Matthew Z MZ, Asif Amimah F AF, Thomas Ebony S ES, Lindley Megan C MC et al.

Quality improvement (QI) programs for healthcare providers have increased childhood immunization coverage. However, practice-level strategies for adult immunization are less clearly defined and may differ from pediatric approaches. To identify and summarize adult immunization QI programs described in published and unpublished literature. We searched PubMed, Embase, ClinicalTrials.gov, and the Networked Digital Library of Theses and Dissertations in December 2023 using terms covering four main concepts (QI, adults, healthcare providers, and immunization). Results were exported to Covidence for deduplication, screening, and data extraction. Articles describing at least one U.S. adult immunization QI program were included. We included 272 studies. QI programs most frequently targeted influenza (64%) and pneumococcal (43%) vaccines and used patient education (49%), patient reminders (38%), provider reminders (36%), and provider education (35%). Most (81%) of the 212 studies assessing vaccine coverage following QI programs found a statistically significant increase, including 72% of the randomized controlled trials, 85% of the quasi-experimental studies, 89% of the cohort studies, and all of the non-randomized trials and meta-analyses. Adult immunization QI programs often focus on reminders and education about influenza and pneumococcal vaccines, and they frequently increased adult immunization coverage. Further research is needed to determine the QI components most effective for adult vaccination.

PMID 42462435
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