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PubMed2026

Pre-clinical immunogenicity and safety evaluation of H2 strain Hepatitis A Inactivated Vaccine in rhesus macaques.

BACKGROUND: Hepatitis A is a viral infection of the liver that can cause mild to severe illness. Currently, two types of HAV vaccines are used worldwide, inactivated hepatitis A vaccines, which are used in most countries, and live attenuated vaccines (H2 and L-A-1 strain), which are mainly used in China. The major disadvantage of live attenuated virus to cause secondary infections among contacts and mutation shifts of the live vaccine strain. The H2 strain was selected for the development of an inactivated hepatitis A vaccine to further reduce biosafety risks. Rhesus macaques high genomic homology with humans and the incubation period after hepatitis A vaccination and human natural infections are similar. We use rhesus macaques to assess immunogenicity and safety of the H2 strain Hepatitis A Inactivated Vaccine. METHODS: The vaccine was assessed in rhesus macaques, divided into four groups (n = 10 per group): the control group (adjuvant buffer; aluminum content 0.35 mg/mL; 2 mL per dose), the low-dose group (320EU, 0.5 mL of 640EU/mL with aluminum content 0.35 mg/mL), the medium-dose group (640EU, 1 mL of 640EU/mL with aluminum content 0.35 mg/mL), and the high-dose group (1280EU, 2 mL of 640EU/mL with aluminum content 0.35 mg/mL). Animals were injected intramuscularly at multiple sites in the hind limbs and received four inoculations at 4-week intervals. Test items including Clinical indicators, immunogenicity indicators and Histopathological examination. RESULTS: No abnormalities were observed in any group in terms of general clinical condition throughout the study period except for slight decreases in body temperature after immunization. Hematological parameters, serum biochemistry indices, and histopathological findings showed fluctuated to different degrees of fluctuation after immunization across all groups. Immunogenicity assessments showed that the inactivated hepatitis A vaccine (H2) induced both humoral and cellular immune responses effectively, and the levels of antibodies increased with certain dose- and time-response trends. CONCLUSION: The inactivated hepatitis A vaccine (H2 strain, human diploid cell) was safe and immunogenic in non-human primates. The results provide strong preclinical support for the further clinical development of this vaccine candidate.

Animals↗

PubMed2026

Immunogenicity and safety of inactivated TZ84- vs. HM175-based hepatitis A vaccines in pediatric populations: A systematic review and meta-analysis.

Individual studies indicate stronger and persistent long-term immunogenicity with TZ84-based than HM175-based hepatitis A vaccines. This systematic review and meta-analysis compared immunogenicity and safety of inactivated TZ84- and HM175-based hepatitis A vaccines in children and adolescents. Studies involving adults, immunocompromised populations, non-comparative designs, non-English publications, and studies with non-extractable outcomes were excluded. MEDLINE/PubMed, Google Scholar, other electronic databases, and grey literature were searched (September-October 2025). Risk of bias was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool, and meta-analyses were performed where appropriate. Seven publications arising from four randomized cohorts (total participants: 3,282) reporting seroconversion rates (SCRs), geometric mean concentrations (GMCs), long-term seroprotection, and adverse events (AEs) were identified. Pooled analyses demonstrated higher SCRs and GMCs with TZ84 than HM175-based vaccines following both one and two doses. SCRs at 1 month [odds ratio (OR): 3.05; 95% confidence interval (CI): 1.88-4.96] and GMCs at 7 months [standardized mean difference (SMD): 0.88; 95% CI: 0.18-1.58; p = .01] both favored TZ84-based vaccines. Long-term follow-up (up to 186 months/15.5 y) showed higher reported anti-HAV antibody concentrations for TZ84-based vaccines. The AEs were comparable between vaccine types (RR: 0.95; 95% CI: 0.76-1.20; p = .69). Evidence was limited by the small number of unique randomized cohorts, geographic concentration in China, heterogeneity across studies, and reliance on surrogate immunogenicity outcomes. Overall, available evidence suggests that TZ84-based hepatitis A vaccines (HAPIBEV™/HEALIVE®) are associated with higher reported antibody responses and greater reported antibody persistence than the HM175-based vaccine (HAVRIX®) in children and adolescents, with comparable safety profiles.Registration: PROSPERO CRD420251154480.

Humans↗

PubMed2026

A multi-center, open-labelled, randomized controlled extended phase III non-inferiority clinical trial to evaluate the immunogenicity and tolerability of poliomyelitis vaccine (Vero cells), inactivated, Sabin strains administered with or without routine infant vaccines.

BACKGROUND: Oral poliovirus vaccine (OPV) has been reported to cause vaccine-derived poliovirus and vaccine-associated paralytic poliomyelitis, and the limited global supply of conventional IPV has led many countries to rely on fractional-dose IPV regimens alongside OPV. The current study aims to assess the sIPV safety and immunogenicity when given concurrently with or in a staggered manner with routine immunization. METHODS: A multi-country, multi-center, open-label, randomized controlled, extended phase III non-inferiority clinical trial was conducted with 1442 healthy infants aged 6-8 weeks from Bangladesh and Pakistan enrolled and randomized into four groups, i.e., co-administration group 1 (group C1), co-administration group 2 (group C2), staggered administration group 1 (group S1) and staggered administration group 2 (group S2). Antibody levels were determined using the collected sera for immunogenicity evaluation. The difference in seroconversion rates between the coadministration group and the staggered administration group is compared using the Cochran-Mantel-Haenszel χ2 (CMH-χ2) test, stratified by study site. Non-inferiority is concluded if the lower bound of the 95% confidence interval (CI) for the rate difference (coadministration group minus staggered administration group) is greater than -10%. The trial was registered prior to patient enrollment at clinicaltrials.gov (NCT05850364), and the protocol and statistical analysis plan are available at https://clinicaltrials.gov/study/NCT05850364. The trial is closed to new participants. FINDINGS: The post-vaccination seroconversion rates for PV I were 90.3% (306/339) in group C1 and 87.0% (261/300) in group S1, for PV II, 91.7% (311/339) in group C1 and 91.3% (274/300) in group S1 and for PV III, 86.4% (293/339) in group C1 and 92.3% (277/300) in group S1. Among adverse reactions (ARs) reported within 7 days of vaccination, the incidence was similarly high in both the co-administration and staggered vaccination groups (92.8% vs. 95.5%). INTERPRETATION: Our results demonstrated favorable safety and immunogenicity of co-administration of sIPV with other routine infant vaccines according to a 3-dose primary immunization schedule.

Humans↗

PubMed2026

Excess iodine induces lipid metabolic disorders by the gut microbiota SCFAs/H2S-p-AMPKα/PPARγ/SREBP-1c pathway in female rats.

With the development of living standards, the problem of excess iodine has long been overlooked. This study aimed to investigate the detrimental effects of long-term excess iodine exposure on lipid metabolism in female Sprague-Dawley rats from the gut-liver axis perspective, and to elucidate the underlying molecular mechanisms by which the gut microbiota and its metabolites mediate iodine-induced lipid metabolic disorders. The results indicated that abnormal iodine nutrition has a negative effect on the health of rats. Specifically, excess iodine not only causes thyroid disorders but also leads to liver lipid metabolism disorders, including elevated serum and hepatic total cholesterol/triglyceride levels and lipid accumulation in the liver. Further investigation revealed that excess iodine causes liver lipid metabolism disorders by altering the gut microbiota, which resulted in an increase in the relative abundance of Desulfovibrio and Lachnospiraceae NK4A136_group, and a decrease in the relative abundance of Akkermansia and Blautia in excess iodine groups. A decrease in the relative abundance of Blautia and an increase in Lachnospiraceae NK4A136_group were strongly correlated with reductions in short-chain fatty acids (acetic, propionic, and valeric acids), whereas an increase in Desulfovibrio was strongly correlated with an increase in H2S. Additionally, acetic acid was negatively correlated with H2S in serum and liver. Excess iodine reduced hepatic p-AMPKα expression while upregulating key regulators of lipid metabolism, including SREBP-1c, PPARγ and ACC1. These changes may represent one of the key mechanisms by which excess iodine induces lipid metabolism disorders through the microbiota-metabolite axis. Overall, these findings suggest that excess iodine influences lipid metabolism through the gut-liver axis. The results of this study provide scientific references and guidance for the appropriate intake of iodine and offer novel insights for early nutritional interventions targeting lipid metabolism disorders.

Journal Article↗

PubMed2026

Comparison of immunogenicity, safety, and efficacy of EVA71 vaccine in children: a systematic review and meta-analysis.

INTRODUCTION: Enterovirus 71 (EV-A71) is a principal cause of hand, foot, and mouth disease (HFMD), potentially leading to severe neurological complications in children. Inactivated EV-A71 vaccines have been introduced. This study compares the immunogenicity, safety, and efficacy of EV-A71 vaccines versus placebo in pediatric populations. RESEARCH DESIGN AND METHODS: Following a PROSPERO-registered protocol, RCTs involving EV-A71 in children were identified via PubMed, Scopus, Cochrane, and ClinicalTrials.gov. Two independent reviewers performed screening, extraction, and RoB assessments (RoB 2.0). RESULTS: Five phase III RCTs involving 36,659 children were included. EV-A71 vaccination significantly increased seropositivity across follow-up periods, including early (RR 5.8), medium-term (RR 3.09), and long-term (RR 2.95) response. Seroconversion was significantly higher in the vaccinated group (pooled RR 13.04, 95% CI 2.80-60.61; p < 0.001). Geometric mean titers, analyzed using the ratio of means approach, were significantly higher in the vaccinated group during early and medium-term follow-up. Vaccine efficacy against EV-A71-associated HFMD exceeded 98% (pooled RR 0.02, 95% CI 0.01-0.09; p = 0.0028; I2 = 50%). Solicited local and systemic adverse events were mild and comparable between groups. CONCLUSION: Inactivated EV-A71 vaccines robust immunogenicity, high clinical efficacy, and an acceptable safety profile in children. Future studies should explore long-term protection, booster schedules, and multivalent formulations against non-EV-A71 serotypes.

Humans↗

PubMed2026

Whole cell inactivated poly-bacterial preparation MV130 effect on nasal mucosal immunity and experimental human pneumococcal carriage: double-blind randomised controlled trial with controlled human infection model.

BACKGROUND: Bacterial mucosal immunotherapy has shown protection of children and adults from both viral and bacterial respiratory infections, offering the potential to reduce antimicrobial use, and hence also control antimicrobial resistance (AMR). Pneumococcal carriage of vaccine type Streptococcus pneumoniae remains high in Malawi despite infant conjugate vaccination and AMR is increasing. We compared nasal inflammation following sublingual bacterial immunotherapy including S. pneumoniae (MV130, Inmunotek, Spain) or placebo and determined the effect in an experimental human pneumococcal carriage model. METHODS: A double-blind, randomised, placebo-controlled trial in healthy adult volunteers was conducted at Queen Elizabeth Central Hospital in Blantyre, Malawi. Participants were randomly allocated to receive MV130 or placebo sublingually once daily for 42 days. Mucosal inflammation (neutrophil to T cell ratio, NTR) was measured in nasal micro-biopsies. Post-treatment, participants were challenged with 160,000 CFU/naris S. pneumoniae 6B (Spn6b). Experimental pneumococcal carriage rates post inoculation were compared between the two arms. All participants completing the study were included in the analysis. Prospective trial registration: PACTR202403820001276. FINDINGS: 107 participants were enrolled and randomised to MV130/placebo between May and December 2024. There were no serious adverse events, complete compliance was good (72%) and all adverse events were mild. 96 participants (53 male, 43 female) completed the study with 52 participants randomised to MV130 and 44 to placebo. There was no difference in mucosal inflammation (neutrophil to T cell ratio) at day 14 of the intervention MV130 NTR median = 0.737 (IQR 0.294, 2.059) and placebo NTR = 0.831 (IQR 0.450, 2.073), p = 0.64. Secondary analyses showed a rise in mucosal neutrophils after MV130 treatment and after experimental pneumococcal inoculation. There was no difference in nasal or serum anti-pneumococcal immunoglobulin or in experimental pneumococcal carriage proportion between MV130 (12/52, 23%) and placebo (10/44, 23%) groups (unadjusted risk ratio 1.02 (CI 0.49-2.12) p = 1.0). INTERPRETATION: MV130 induced non-specific mild neutrophil inflammation of the nasal mucosa but had no protective effect against experimental human pneumococcal carriage. FUNDING: Wellcome Trust.

Humans↗

PubMed2026

Immunogenicity of Two Versus Three Doses of Hepatitis B Vaccine When Administered to Children Aged 2-18 Months: A Randomized Clinical Trial.

BACKGROUND: A 2-dose hepatitis B vaccination schedule is highly immunogenic in children aged ≥1 year, but data for infants are scarce. Our goal was to compare the immunogenicity of 2- and 3-dose hepatitis B vaccination schedules in this population. METHODS: Children in the experimental group were recruited at 2 months of age and randomized to receive a homologous (Infanrix-hexa/Infanrix-hexa) or heterologous (Infanrix-hexa/Twinrix) 2-dose schedule at 2 and 12 months. Children in the control group were recruited at 18 months and had received a homologous 3-dose schedule (Infanrix-hexa/Infanrix-hexa/Infanrix-hexa) at 2, 4, and 18 months. All groups received a challenge dose (Twinrix) 3 years later. RESULTS: One month after the primary series, seroprotection rates (anti-HBs ≥10 mIU/mL) were high and similar among the 3 groups (heterologous 2-dose, 91.7%; homologous 2-dose, 90.9%; 3-dose, 94.2%). Geometric mean titers (GMTs) were lower in the 2-dose groups than in the 3-dose group. Post-challenge dose, the majority exhibited an anamnestic response, similar across all 3 groups (heterologous 2-dose, 97.2%; homologous 2-dose, 95.5%; 3-dose, 92.7%). GMTs were numerically higher in the heterologous 2-dose group (9380.5 mIU/mL) than in the 3-dose group (6900.6 mIU/mL) (P = .4). The proportion exhibiting local reactions was significantly lower after the heterologous 2-dose schedule than after the homologous 2-dose schedule. CONCLUSIONS: The anamnestic response 3 years after 2-dose (2 and 12 months) and 3-dose (2, 4, and 18 months) hepatitis B vaccination schedules was similar. The heterologous 2-dose schedule was more immunogenic and less reactogenic than the homologous 2-dose schedule.

Humans↗

PubMed2026

Adherence and efficacy of the 0 - 7 - 21-day versus the 0 - 1 - 6-month hepatitis B vaccination schedules among people who use drugs: a two-year randomized controlled trial.

BACKGROUND: To compare the adherence and efficacy between the 0 - 7 - 21-day and the 0 - 1 - 6-month hepatitis B virus (HBV) vaccination schedules among people who use drugs (PWUD) in China. RESEARCH DESIGN AND METHODS: A randomized controlled trial was conducted in 1261 HBV-susceptible PWUD from compulsory isolated detoxification centers (CIDCs) and methadone maintenance treatment (MMT) clinics in Xi'an. A 20 µg per-dose vaccine was used. HBV surface antibody (anti-HBs), surface antigen, and core antibody were tested at months 7, 15, and 22 after the first dose. RESULTS: Third-dose coverage was significantly higher in the 0 - 7 - 21-day group (74.40%) than in the 0 - 1 - 6-month group (51.58%, p < 0.001), mainly driven by participants from CIDCs (77.75% vs. 45.69%). Anti-HBs positive rates at months 7, 15, and 22 among participants who completed all three doses were significantly higher for the 0 - 1 - 6-month schedule (90.71%, 76.82%, and 67.35%) than for the 0 - 7 - 21-day schedule (74.23%, 49.40%, and 40.95%; all p < 0.001). HBV infection incidence was similar between schedules, but significantly different between vaccinees and non-vaccinees (p = 0.018). CONCLUSIONS: The 0 - 7 - 21-day schedule substantially enhances three-dose completion in PWUD, but induces a notably weaker anti-HBs response and persistence. Schedules should be selected based on the management models for PWUD and their individual characteristics. CLINICAL TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR1900022403).

Humans↗

PubMed2026

A randomized trial of viral vector and adjuvanted protein HBV therapeutic vaccine in people with chronic hepatitis B on nucleos(t)ide analogs.

BACKGROUND: This study assessed the safety, efficacy, and immunogenicity of a therapeutic immunization strategy aimed at reaching a functional cure for chronic hepatitis B (CHB), relying on a heterologous prime-boost with viral vectors ChAd155-hIi-HBV and MVA-HBV, combined with sequential or concomitant administration of adjuvanted recombinant HBV proteins (HBc-HBs/AS01B). METHODS: This single-blind, randomized, controlled, first-in-human, phase 1/2 trial enrolled adults aged 18-65 years with HBeAg-negative CHB, virally suppressed on nucleos(t)ide analogs (NAs), with HBsAg >50 IU/mL. Participants received NAs and the following regimens of 4 doses (8-week intervals): sequential administration of ChAd155-hIi-HBV, MVA-HBV, and 2 HBc-HBs/AS01B doses; co-administration of ChAd155-hIi-HBV+HBc-HBs/AS01B, followed by 3 co-administered MVA-HBV+HBc-HBs/AS01B doses; 4 HBc-HBs/AS01B doses; 2 placebo doses followed by ChAd155-hIi-HBV and MVA-HBV administered alone or with HBc-HBs/AS01B; or 4 placebo doses. Safety, efficacy (≥1-log decrease in quantitative (q)HBsAg or HBsAg loss 24 weeks post-dose 4 [day (D)337]), antibody, and T-cell responses were evaluated. RESULTS: In all, 134 participants were vaccinated. Grade 3 solicited adverse events (AEs) (median duration: 2-3 days) were more frequent after co-administration (systemic: 59.3%; administration-site: 33.3%) than sequential administration (systemic: 10.3%; administration-site: 12.8%) of high-dose viral vectors and proteins. No vaccine-related or fatal serious AEs were reported. After 4 doses, no participant had HBsAg loss or ≥1-log decrease in qHBsAg (D337 vs. D1). Co-administration induced the strongest anti-HBs response (73.7% achieved anti-HBs ≥10 mIU/mL 2 weeks post-dose 4 vs. 40.0% after sequential administration). Both sequential and co-administration induced HBc-specific CD4+ and CD8+ T-cell responses, with a prime-boost effect of the viral vectors. CONCLUSIONS: Heterologous prime-boost with ChAd155-hIi-HBV and MVA-HBV, combined with sequential or co-administration of HBc-HBs/AS01B, had an acceptable safety profile, were moderately immunogenic, but no participants showed the expected efficacy outcome.

Humans↗

PubMed2026

LINE-1 repeats are a defining feature of the Xce.

During early development, female mammals inactivate one X chromosome to balance their X-linked gene dosage with males. While allelic choice is random in inbred mouse populations, choice can be significantly skewed in interstrain hybrids. The genetic basis of skewing has long been attributed to the mysterious "X chromosome controlling element(s)" (Xce) with different strengths among species, subspecies, and strains. When two X-chromosomes with different Xce strengths are inherited by offspring, the X chromosome with the stronger Xce will have a higher probability of remaining active. Here, we provide evidence that L1Tf repeats-a subfamily of long interspersed nuclear elements 1-plays a role in determining Xce strength. L1Tf elements form a condensed core within the inactive X (Xi) territory. Mouse strains with varying Xce strengths differ in the L1Tf copy number on the X chromosome, with the strength of the Xce allele being inversely related to L1Tf copy number. L1Tf expression mediates the Xce effect. However, in contrast to a prior report, L1Tf RNA does not coat the Xi. Rather, L1Tf promotes condensation of the Xi core. Intriguingly, L1Tfs recruit and sequester YY1 from active genes, accelerating XCI in cis. Thus, L1Tf copy number, expression, and binding of YY1 are key defining features of the Xce. We propose a model in which the Xce influences the choice of Xist alleles by promoting YY1 binding to the nucleation site for the initiation of Xist spreading.

Animals↗

PubMed2026

Genetic diversity and recombination of NA-PRRSV field strains in Vietnam: Implications for vaccine efficacy.

Porcine reproductive and respiratory syndrome (PRRS) causes severe reproductive losses in pregnant sows and piglets, resulting in substantial economic impact on the swine industry worldwide. However, due to the significant genetic diversity and rapid evolutionary changes of the pathogen, continuous surveillance and detailed genetic analysis of circulating strains are essential. The current study aimed to evaluate the genetic diversity of the hypervariable (HV) region of non-structural protein 2 (nsp2) among North American PRRSV strains isolated from swine farms in Vietnam. Phylogenetic analysis and multiple sequence alignment were conducted to determine subtype classification and assess genetic variability. A total of 48 field isolates were obtained, of which 12.5% belonged to classical NA-PRRSV, 16.6% to NADC30-like and 70.9% to HP-PRRSV, primarily distributed across sublineages 1.4, 5.1, 8.7 and 8.9. Amino acid comparisons found multiple insertions, deletions and substitutions at various positions within the hypervariable region of nsp2. The study revealed substantial genetic variation in the HV region of nsp2 among NA-PRRSV field strains, largely associated with recombination and immune escape. These findings highlight epidemiological risks to vaccine efficacy and underscore the need for continuous molecular surveillance to support effective PRRSV control in Vietnam.

PRRSV↗

PubMed2026

Development and protective efficacy of a live attenuated vaccine candidate against goose astrovirus.

Goose astrovirus (GAstV) is a significant pathogen affecting goslings by inducing visceral gout, yet no commercial vaccine is currently available. This study involved the serial passaging of the GAstV-GXNN strain in LMH cells to investigate alterations in viral replication, genomic stability, and pathogenicity, as well as to assess the potential of a vaccine candidate. The findings indicated that the viral titer increased progressively with each passage, reaching 107.35 TCID50/mL by the 120th passage (GAstV-GXNNP120). Whole-genome sequencing revealed the presence of 6, 19, 26, and 28 nucleotide mutations at the 30th, 60th, 90th, and 120th passages, respectively. Pathogenicity assays demonstrated a reduction in virulence with successive passages, culminating in the complete attenuation of GAstV-GXNNP120, which did not induce clinical signs or lesions in one-day-old goslings. Following five successive passages in goslings, the attenuated strain exhibited stable genetic characteristics without any reversion to virulence. Goslings aged one day, inoculated with GAstV-GXNNP120 at dosages ranging from 102.0 to 105.0 TCID50, developed neutralizing antibodies by the third day post-vaccination. Antibody levels increased in a dose-dependent manner, peaking at day 21 and remaining elevated through day 42. Challenge experiments utilizing the virulent GAstV-GXNN strain revealed that groups vaccinated with doses of 103.0 TCID50 and above achieved complete protection. These groups exhibited no clinical symptoms or pathological damage post-challenge, and both tissue viral loads and virus shedding levels were significantly reduced compared to the control group. Consequently, the minimum effective vaccination dose was established at 103.0 TCID50. These results provide a crucial foundation for the development of a live attenuated GAstV vaccine.

Animals↗

PubMed2026

Meta-analysis of growth and inactivation kinetics of Legionella.

Quantitative risk assessments intended to inform evidence-based water management plans and public health targets for Legionella in engineered water systems are constrained by fragmented and heterogeneous growth and inactivation kinetics. We conducted a meta-analysis of 25 growth and 39 thermal- and chemical-inactivation studies, fitting microbial persistence models to harmonize parameters. Nonlinear models outperformed first-order formulations, indicating that lag phases and resistant or protected subpopulations are central to Legionella persistence. Random forest analysis identified environmental and methodological drivers of variability based on 226 growth rates and reduction times for thermal (209) and chemical (135) inactivation. Growth was primarily governed by temperature, nutrient availability, and compatible Legionella-host pairings; thermal inactivation by quantification method, temperature, and turbidity; and chemical inactivation by inoculum size, disinfectant type, concentration, and host-associations. Accordingly, temperature-dependent growth parameters and exposure metrics for heat, free-chlorine, and monochloramine, expressed as TT (Temperature×time) and CT (Concentration×time), were derived as condition-specific inputs for predictive models. Growth optima around 37-40 °C, together with lag-time estimates, indicate that hot-water temperature setbacks and energy-saving practices may favor Legionella proliferation under repeated or prolonged lukewarm exposure. Culture- and viability-based TT differences highlight the need to consider viable‑but-non-culturable persistence in monitoring programs. CT comparisons suggest monochloramine may be advantageous because of its lower apparent sensitivity to host-associated protection. Although limited by restricted experimental conditions, the findings show that predictive models should account for microbial ecology, water matrix effects, and quantification endpoints. Future kinetic studies should prioritize realistic multi-host systems, strain pre-adaptation, complementary viability measurements, and standardized protocols and reporting to ensure reproducibility and enable robust system-level predictive modeling.

Legionella↗

PubMed2026

Genomic determinants underlying biogenic amine detoxification phenotypes in food-associated lactic acid bacteria: Mechanism, evolutionary origin, and relevance to fermented food safety.

Biogenic amines (BAs) are toxic metabolites that accumulate in fermented foods and pose significant food safety concerns. Although several lactic acid bacteria (LAB) have previously been reported to exhibit strain-specific BA-degrading phenotypes, the genetic determinants underlying these activities have remained largely uncharacterized. Here, we analyzed 8251 LAB genomes to validate BA-degrading phenotypes. We predicted five BA-associated genes, including two direct biogenic amine-degrading genes (BADGs), mco and patA, and three polyamine-modifying genes (PMGs), speG, paiA, and bltD. Among BADGs, mco was broadly distributed across LAB and strongly enriched across food-associated niches. patA, organized within a conserved potD-glnB-potABC-patA cassette, is a putative, functionally distinct BADG in LAB, revealing a nitrogen-responsive polyamine uptake-catabolism module. Phylogenomics, phylogenetic reconciliation, and synteny analysis established that all five genes entered the LAB through episodic horizontal gene transfer followed by lineage-specific fixation. GC compositional bias and mobile genetic element association further corroborated the horizontal origin of the two BADGs. Structural analysis confirmed the conservation of catalytic core residues of BADGs across LAB, indicating strong purifying selection. Phenotype-to-genotype correlation with experimentally reported LAB suggested mco as a reliable genomic predictor of degrading phenotype. Integration of degradation and biosynthetic profiles predicted multiple LAB species capable of both synthesizing and degrading BA, along with 1823 genomes with degradation potential but lacking detectable BA biosynthesis genes. This study provides the first large-scale genome framework linking BA-degrading phenotypes with their genetic determinants in LAB and offers a rational basis for selecting BA-detoxifying strains for fermented food applications.

Biogenic Amines↗

PubMed2026

Serotypic and Genomic Diversity of Vibrio anguillarum in Rainbow Trout Farms in Turkey: Implications for Vibriosis Control and Vaccine Candidate Selection.

Outbreaks of vibriosis caused by Vibrio anguillarum are a persistent constraint on rainbow trout (Oncorhynchus mykiss) aquaculture. However, information on the population structure of field strains in Turkey has been lacking. Here, we report the first systematic serotypic, proteomic, and genomic characterization of 23 V. anguillarum isolates collected over 10 years from rainbow trout farms located in six major aquaculture regions of Turkey. Serological analyses based on microagglutination, supported by ELISA characterization of hyperimmune sera, identified a clear predominance of serotype O1, whereas isolate V12 exhibited a non-agglutinating, atypical O-antigen profile. Protein profiling (SDS-PAGE) and immunoblotting showed largely conserved whole-cell protein patterns among the isolates, but distinct immunogenic bands at 14, 18, and 40 kDa were detected in isolates V18 and V21. Long-read whole-genome sequencing revealed that most Turkish isolates grouped within the global O1 clade, while V12, V25, and V28 isolates occupied more distant branches. Comparative genomics demonstrated a conserved core virulence gene set (RTX toxins, siderophore and iron-uptake systems, motility and adhesion factors, Type VI secretion system), with strain-dependent variation in accessory loci such as anguibactin and T6SS-I. Experimental infections of rainbow trout demonstrated significant differences in virulence among isolates (p < 0.05), with the V18 isolate showing high, the V15 intermediate, and the V12 low-mortality rates. By elucidating the relationship among the serotype, immunogenic protein profiles, virulence gene repertoires, and in vivo pathogenicity, this study provides a comprehensive overview of the antigenic and genomic diversity of Vibrio anguillarum isolates from Turkey. Notably, the identification of V18 and V21 as promising candidate strains for further vaccine evaluation, characterized by high virulence and unique immunogenic features, provides a scientific foundation for the development of serotype-specific vaccination strategies to mitigate vibriosis-associated losses in aquaculture.

Animals↗

PubMed2026

Genotype II Live-Attenuated ASFV Vaccine Bearing 24 Genes Deletion in 3 Independent Regions Is Able to Provide Complete Protection Against Homologous Lethal Challenge.

African swine fever (ASF) is an acute, febrile, and highly contagious infectious disease of swine with the etiological agent of African swine fever virus (ASFV). The mortality rate of virulent strains is as high as 100%. Strengthening biosafety is so far the most effective way to prevent and control ASF. Therefore, it is urgent to develop a safe and effective vaccine. In this study, a Genotype II live-attenuated ASF vaccine bearing 24 genes deletion in 3 independent regions was constructed based on the highly virulent Eurasian strain ASFV CN/GS 2018 backbone. The resulting mutant ASFV-Δ24 is characterized by complete deletion of 24 genes distributed in 3 genomic positions of 852 to 11 468, 19 732 to 22 929, and 179 519 to 180 617, among which MGF100 and whole MGF300 families are pioneeringly removed. The ASFV-Δ24 displayed a delayed and reduced replication kinetics as well as aberrant icosahedral empty particles devoid of a nucleoid when compared to the parental virus. Animal experiments showed that ASFV-Δ24 was completely attenuated in animals as evidenced by stable body temperature and no ASF-compatible clinical signs in vaccinated pigs. The ASFV-Δ24 could provide complete homologous protection against lethal challenge, as vaccinated pigs demonstrated boosted antibody response, transient but low levels of viremia in blood and virus titers in organs as well as almost undetectable viral shedding. Gene deletions in multiple regions are helpful for prevention of virulence reversion. These results indicate that ASFV-Δ24 can be used as an effective and promising candidate vaccine to control the spread of ASFV.

Animals↗

PubMed2026

Safety of a quadrivalent meningococcal conjugate vaccine (MenACYW-TT) administered concomitantly with routine pediatric vaccines in healthy infants and toddlers in USA and Puerto Rico: Results from a Phase III, randomized, active-controlled study.

MenACYW-TT, a quadrivalent meningococcal tetanus toxoid-conjugate vaccine, is approved for prevention of invasive meningococcal disease in infants ≥ 6 weeks of age in the USA. This Phase III study (NCT03673462; September 17, 2018 - March 16, 2023) evaluated the safety of MenACYW-TT compared with a licensed quadrivalent meningococcal oligosaccharide diphtheria CRM197-conjugate vaccine (MenACWY-CRM) when administered concomitantly with routine pediatric vaccines in healthy infants and toddlers in a four-dose series (3+1 schedule). Participants were randomized 3:1 to receive MenACYW-TT (Group 1; n = 2080) or MenACWY-CRM (Group 2; n = 697) at 2, 4, 6, and 12 months of age, with concomitant administration of routine pediatric vaccines (DTaP5-IPV/Hib, PCV13, rotavirus, hepatitis B, MMR, and varicella vaccines). Safety assessments included immediate unsolicited adverse events within 30 minutes post-vaccination, solicited injection site and systemic reactions within 7d, unsolicited AEs within 30d, serious adverse events (SAEs) including adverse events of special interest (AESIs), and medically attended adverse events (MAAEs) throughout the study. MenACYW-TT and MenACWY-CRM were overall well tolerated, and safety profiles were comparable. Solicited injection site reactions occurred in 84.9% and 84.6% of participants in Groups 1 and 2, respectively; solicited systemic reactions in 87.1% and 88.2%, respectively. During the entire study, 5.2% in Group 1 and 3.0% in Group 2 experienced at least one SAE; 0.9% and 0.1%, respectively, reported at least one AESI. Three deaths occurred in Group 1. All SAEs, AESIs, and deaths were unrelated to study vaccines. This study supports the safety profile of MenACYW-TT in infants and toddlers aged ≥ 6 weeks.Study registration: Clinicaltrials.gov: NCT03673462; EudraCT: 2019-004459-35.

Child, Preschool↗

PubMed2026

Systematic review of the mutations in the active antigenic site Ø of the prefusion F protein of the Respiratory Syncytial Virus (RSV) following the implementation of monoclonal antibody prophylaxis.

BACKGROUND: Monoclonal antibody (mAb) nirsevimab, which targets the antigenic site Ø of the prefusion F protein (pre-F) of RSV, was introduced for RSV prophylaxis in several countries. METHODS: A systematic search was conducted between January 1, 2022, and July 31, 2026 for studies analyzing substitutions within the epitope of pre-F RSV protein, which is the target of nirsevimab, after the implementation of the mAb. We searched across PubMed, Scopus, Web of Science and ClinicalTrial.gov for studies involving children with confirmed RSV infection, that conducted genomic analysis. RESULTS: Seven studies (five observational and two randomized controlled trials) including 2156 RSV-positive samples (RSV-A: 1347, RSV-B: 809) were analyzed. RSV-A strains showed limited variability within antigenic site Ø, with K65R being the most common substitution and K209E being the only intermediate-resistance RSV-A substitution. RSV-B strains demonstrated substantially higher substitution frequencies, particularly involving I206M, Q209R, and S211N. Most identified substitutions appeared to represent naturally occurring polymorphisms and retained susceptibility to nirsevimab, while multiple RSV-B substitutions and combinations involving residues 64-68 and 204-208 demonstrated reduced susceptibility or high-level resistance. Resistance-associated variants were detected in 28 of 2156 (1.3%) RSV-positive samples and exclusively among nirsevimab breakthrough infections. In a sub-analysis restricted to nirsevimab-treated individuals, resistance-associated variants were significantly more frequent among RSV-B than RSV-A (9.8% vs 0.5%; p < 0.001). CONCLUSION: Most substitutions that were detected within the nirsevimab antigenic site reflect ongoing natural RSV evolution and do not significantly affect nirsevimab susceptibility. However, detection of resistance-associated variants highlights the importance of continuous genomic and phenotypic surveillance.

Humans↗