Background and Aims:
Otitis media (OM) is the most common childhood disease diagnosed among Australian children and the leading cause of hearing loss in Aboriginal and Torres Strait Islander children. Outer membrane vesicles (OMVs) represent a promising new adjuvant platform because they naturally mimic bacterial membranes and provide strong innate immune stimulation while also displaying high immunogenicity. In this project, we aimed to harness OMVs as an adjuvant system, while genetically modifying them to remove immunodominant, strain-variable proteins, thereby enhancing their potential to promote cross-protective responses when combined with conserved recombinant antigens.

Methods:
Novel recombinant protein antigens from NTHi and M. catarrhalis were cloned, expressed in E. coli, and purified by immobilized metal affinity chromatography. Genetically modified M. catarrhalis OMVs were produced by engineering knockout mutants, purified by ultracentrifugation, and characterized for yield and composition. Mice were immunized with recombinant antigens formulated with these OMVs, and sera were analyzed by ELISA, and bactericidal assays with complement deposition assays in progress.

Results:
Recombinant NTHi and M. catarrhalis antigens were successfully expressed and purified. Genetically modified OMVs with reduced strain variability were generated and characterized. ELISA data indicate that OMV-adjuvanted formulations elicit strong antigen-specific antibody responses in mice and provide broader coverage against both homologous and heterologous strains.

Conclusions:
This study highlights the use of engineered OMVs as a novel adjuvant platform to enhance immunogenicity and broaden protection against diverse OM pathogens. The integration of recombinant protein antigens with adjuvant-active OMVs offers a promising new strategy to overcome the limitations of current vaccines for OM.

Objective: The aim of this study was to analyze vaccination coverage at 24 months of age among children born in 2017 and 2018, residing in Teresina, Piauí. Methods: This was an analytical, cross-sectional, household survey study, with cluster sampling of census tracts stratified according to socioeconomic conditions (A: high; B: medium; C: low; D: very low). Socioeconomic data were obtained through structured interviews with guardians, and vaccination records were obtained through photographs of the vaccination booklet. Indicators of coverage, access, adherence, and abandonment of vaccination were estimated using percentage frequencies and 95% confidence intervals (95% CI), applying sample weights. Crude (OR-b) and adjusted (OR-a) odds ratios were calculated using univariate and multivariate logistic regression to identify factors associated with vaccination incompleteness. We considered basic coverage to be the application of BCG (1 dose), Hepatitis B (1), Pentavalent (3 doses), IPV (3), VORH (2), Pneumococcal-10 (2), Meningococcal-C (2) and Yellow Fever (1). Complete coverage included the basic scheme plus MMR (2), boosters of Pneumococcal-10, Meningococcal-C, OPV and DTP (1 each), Hepatitis A (1) and Varicella (1). Results: The final sample of 899 children presented complete vaccination coverage of 63.6% (n=571; 95% CI: 55.49–71.07), being higher in stratum B (74.9%; 95% CI: 60.65–85.31). Incompleteness of the basic scheme was associated with crowded households (OR-b=2.79) and mothers with more than one child (OR-b=1.44; OR-a=2.60). For the complete scheme, it was associated with maternal multiparity (OR-b=1.19; OR-a=1.59), 9–12 years of schooling (OR-b=2.30), and family income >BRL 8,000 (OR-b=3.02; OR-a=6.25). There was a lower chance of incompleteness among children in fourth position or higher in the birth order (basic: OR-a=0.02; complete: OR-a=0.15) and among mothers with ≥16 years of schooling (basic: OR-b=0.33; OR-a=0.22). Conclusion: Insufficient and heterogeneous vaccination coverage was observed, with disparities between socioeconomic strata, between basic and complete schemes and divergence in relation to the SI-PNI data.

Abstract: A one-dose varicella vaccination program for children aged 1-14 years was introduced in Guangzhou in 1999. Since November 2017, a two-dose varicella vaccination program has been implemented, with the first dose for children aged 12-24 months and the second dose for children aged 4-6 years. To evaluate the effectiveness of the two-dose varicella vaccination strategy in Guangzhou, we conducted an interrupted time series (ITS) analysis using monthly reported varicella incidence data (2011-2024) and demographic statistics. In total, 225,497 varicella cases were reported between January 2011 and December 2024. The annual average reported incidence rate from 2011 to 2024 was 106.59 per 100,000. Prior to the two-dose varicella vaccine intervention (2011-2017), the annual average reported incidence rate was 126.80 per 100,000, while the post-intervention (2018-2024) annual average reported incidence rate was 91.14 per 100,000. Varicella cases in Guangzhou exhibited a bimodal distribution, peaking primarily between October and January (accounting for 42.14% of all cases, n=95,023) with a secondary peak in May. For the general population, varicella incidence showed a non-significant pre-intervention increasing trend of 0.3% per month (t = 2.27, P = 0.294). Post-intervention, a significant level change of +7.719 per 100,000 (t = 10.024, P < 0.001) was observed, with a slope change of -2.1% (t = -9.956, P < 0.001). This corresponds to a sustained monthly decline in incidence of 1.8%, indicating a statistically significant long-term reduction. Across age groups, the 4-6-year-old group demonstrated the most substantial decrease (a 3.8% monthly reduction), followed by the 7-9-year-old group. All age groups exhibited statistically significant long-term declining trends. To optimize varicella control, we suggest a phased introduction of the two-dose vaccine into China’s NIP, with Guangzhou as the pilot site focusing on 4-6-year-olds, while assessing the cost-effectiveness to guide future policy.

Introduction:

Hepatitis B is a potentially severe viral infection, associated with the risk of progression to cirrhosis and hepatocellular carcinoma (WHO, 2024). Vaccination, available through the Brazilian Unified Health System (SUS) for all unvaccinated individuals, is the main preventive measure (Brazil, 2023). In children, the schedule includes four doses: at birth and at 2, 4, and 6 months of age, with the last one administered as part of the pentavalent vaccine. The birth dose, recommended within the first 24 hours of life and up to the 30th day, is critical to preventing vertical transmission (CDC, 2023; Brazil, 2022). The national vaccination coverage (VC) target for this dose is 95% (Brazil, 2023). VC is calculated by dividing doses administered by the number of live births, multiplied by 100 (Brazil, 2021). This study specifically assessed the coverage of the hepatitis B birth dose, without analyzing the completion of the full vaccination schedule.

Methods:
This descriptive study used secondary data from the National Health Data Network (RNDS) on annual coverage of the hepatitis B birth dose administered within 30 days of life, from 2016 to 2025. For 2025, data up to May were included. Coverage was compared to the 95% target and analyzed descriptively. Only the birth dose was evaluated, excluding subsequent doses of the schedule.

Results:
From 2016 to 2018, coverage ranged from 81.75% to 88.40%. In 2019, it declined to 78.57%, with sharper drops during the COVID-19 pandemic, reaching 65.77% in 2020 and 67.03% in 2021. Recovery was observed in 2022 (82.76%), reaching 84.54% in 2023, 94.90% in 2024, and 85.01% up to May 2025. No year consistently achieved the 95% target.

Conclusion:
Coverage of the hepatitis B birth dose in Brazil has fluctuated over the past decade, with a pandemic-related decline and a partial recovery thereafter. As the analysis was limited to the birth dose, data on the completion of the full series were not included. Strengthening neonatal vaccination strategies is essential to ensuring the prevention of vertical transmission.

Introduction:
Cat allergies are predominantly caused by the major cat allergen Fel d 1. Vaccination against Fel d 1 is an emerging approach for cat allergy immunotherapy, with the goal of generating strong Fel d 1-specific IgG responses, which protect from allergy. In this study, we assessed the immunogenicity of a novel vaccine based on Eggplant Mosaic Virus (EMV) virus-like particles (VLPs) engineered to display Fel d 1. Our aim was to compare the impact of administration routes and prime-boost strategies on immune responses in mice.

Methods:
Fel d 1 was genetically fused to the EMV capsid protein and expressed in E. coli. Mice were immunized with EMV-Fel d 1 VLPs, control EMV VLPs alone, or recombinant Fel d 1 protein using homologous or heterologous prime-boost regimens via subcutaneous or intranasal routes. Serum samples were collected to evaluate the Fel d 1-specific IgG responses using ELISA.

Results:
We found that both homologous and heterologous vaccination strategies led to strong Fel d 1-specific IgG responses, with levels increasing after the booster dose. The average log(OD₅₀) value rose from ~2.2 on day 14 (after prime) to ~3.6 on day 28 (after boost). By day 28, the IgG1, IgG2b, and IgG3 subclasses were prominently elevated, whereas IgG2a levels remained comparatively low. The avidity of Fel d 1-specific IgG improved following the booster doses. Interestingly, priming with the EMV-Fel d 1 VLPs resulted in robust IgG responses, regardless of the boosting agent—even when boosted with recombinant Fel d 1 protein.

Conclusion:
EMV-Fel d 1 VLP vaccines triggered robust and specific IgG responses, regardless of the prime-boost strategy used. These results support the continued development of EMV-based VLP platforms as a promising approach for cat allergy immunotherapy.

Hantaviruses infect a range of animal hosts, with rodents serving as reservoirs and transmitting the virus to humans through aerosols of their secretions and excretions. These zoonotic infections can lead to Hantavirus Cardiopulmonary Syndrome (HCPS), which in Chile and Argentina is caused by the Andes virus (ANDV). ANDV is particularly concerning due to its >40% mortality rate and unique capacity for person‑to‑person transmission. To date, no vaccine or therapeutic has been approved by the FDA or equivalent agencies.

In this work, the GPC gene fragment of ANDV, which encodes the envelope glycoproteins Gn and Gc, was integrated into the Autographa californica multiple nucleopolyhedrovirus (AcMNPV) genome using the MultiBac system. The construct was designed for dual expression under the polyhedrin (Polh) promoter for insect cells and the CMV promoter for mammalian cells. Although the GPC fragment was placed under both promoters, only robust expression under Polh has been confirmed, guiding current optimization efforts for mammalian expression. The resulting pseudotyped baculovirus showed strong expression and was successfully amplified to titers exceeding 10⁸ in Sf21 and Sf9 insect cells. The presence and localization of the glycoproteins were confirmed by Western blot using hybridoma-derived monoclonal antibodies and by indirect immunofluorescence assay (IFA). Ongoing work includes immunogold electron microscopy to visualize the ANDV´s glycoproteins on the virion surface and inoculation studies in Syrian hamsters to evaluate immunogenicity and neutralizations activity. While current experimental efforts may prove encouraging, they will be critical for establishing the immunogenic potential of the system and confirming its relevance as a vaccine platform. Although baculovirus-based pseudotyped vaccine candidates have been developed for other pathogens, this system represents a novel application in the context of ANDV. Its modular design and engineering flexibility may further support adaptation for antigen delivery or evaluation in other emerging infectious diseases.

Both humoral and cellular immune responses are known to be crucial in the fight against SARS-CoV-2.

The aim of this work was to evaluate the immunogenicity profile of a bivalent mRNA vaccine encoding a multi-epitope T-cell immunogen and a B-cell immunogen as a receptor-binding domain of the S protein of the SARS-CoV-2 virus in BALB/c mice.

Two mRNA vaccines were obtained: mRNA-BSI encoding fragments of the S, M, N, and E proteins of the SARS-CoV-2 virus enriched with the large number of T-cell epitopes and mRNA-RBD encoding the receptor-binding domain (RBD) of the SARS-CoV-2 S protein. BALB/c mice were immunized with 10 μg of individual mRNA preparations or a 10 μg + 10 μg mixture intramuscularly in LNP vehicles twice with a three-week interval.

RBD-specific ELISA and neutralization assay (Wuhan and Omicron (BA.5.2) strains) showed an 2–4-fold increase in antibody titers in sera of mice immunized with the mixture of mRNA constructs compared to the group of mice that received only mRNA-RBD (mRNA-BSI did not induce a humoral response).

A T-cell response assay showed that mice that received the bivalent mRNA vaccine had a higher level of IFN-γ T-cell activation compared to the group that recieved the individual mRNA vaccine. In addition, the increases of IL-2 and TNF-α were not particularly significant, and the absence of IL-4 was noted.

The results indicate the formation of a pronounced humoral and T-cell response and a Th1 shift in mice that received the bivalent mRNA vaccine, encoding B-cell and T-cell immunogens.

The study was carried out as part of the state assignment of the FBIS SRC Virology and Biotechnology "Vector" of Rospotrebnadzor.

The use of nanoparticles (NPs) has been of great interest in the field of vaccinology for the generation and development of nanocarriers for new oral vaccines. Zein NPs have become a promising option since protein NPs show several advantages, such as biocompatibility and a longer antigen release. To use these NPs as an oral vaccine model, they can be conjugated with a molecule that improves their recognition by the intestinal dendritic cells. Folic acid has been used due its high affinity for dendritic cells, making it an ideal molecule for conjugation with NPs. In this work, a relatively simple and highly reproducible method was established to generate zein-based nanocarriers: pure zein NPs and zein NPs with covalently linked folate. Two different strategies for covalent bond formation between the zein NPs and NHS–folate were evaluated, one for the formation of zein NPs with folate on their surface (ZN-FA NPs) and another one for zein NPs with folate both on their surface and inside of them (ZN(FA) NPs). The obtained NPs were characterized in terms of shape, size, polydispersity, and zeta potential using dynamic light scattering (DLS) analysis and visualized via transmission electron microscopy (TEM). The synthesized ZN-FA NPs and ZN(FA) NPs showed a spherical shape with low polydispersity and an average particle size of 229.88.42 ± 59.52 nm and 293.70 ± 69.19 nm, respectively, according to the TEM analysis, while the DLS analysis showed a hydrodynamic radius of 366.42 ± 39.84 nm and 455.77 ± 91.55 nm, respectively. Fourier-transform Infrared spectroscopy (FTIR) confirmed the successful conjugation of folate to the NPs, while UV-Vis spectrophotometry determined the concentration of folate in the NPs and a protein adsorption efficiency of 45.44% and 41.00% for ZN-FA NPs and ZN(FA) NPs, respectively. Furthermore, cytotoxicity assays in the DC2.4 dendritic cell line demonstrated that the NPs are not cytotoxic.

Background:

Head and neck squamous cell carcinoma (HNSCC) is a recurrent cancer of the oral cavity, pharynx, and larynx, closely linked to tobacco and alcohol use and the oral microbiome [1,2]. Standard treatment relies on surgery, radiotherapy, and chemotherapy, while immune checkpoint inhibitors (ICIs) are used in advanced disease but achieve modest response rates (~15-20%) and frequent resistance [3–5]. Cancer vaccines that expand antigen-specific T cells may augment ICI efficacy by overcoming tumor immunosuppression [6,7]. This review examines current clinical evidence on such combination strategies in HNSCC.

Methods:

A systematic search of PubMed, Wiley Online Library, and ASCO publications identified clinical studies of therapeutic vaccines combined with ICIs in HNSCC, published between January 2020 and July 2025. Eligible trials reported clinical outcomes including survival, response rates, or pathologic regression.

Results:

Four studies met the inclusion criteria. In the randomized FOCUS trial, Antonia et al. found that UV1 vaccination with pembrolizumab in 78 recurrent/metastatic PD-L1+ patients achieved a 6-month progression-free survival (PFS) of 30% versus 40% with pembrolizumab alone; median overall survival (OS) was 12.6 vs 13.1 months, with lower response rates in the vaccine arm [8]. Massarelli et al. showed that ISA101 plus nivolumab in 24 HPV-16+ patients yielded an ORR of 33%, median OS 15.3 months, and durable complete responses, linked to interferon-γ gene expression [9]. In a neoadjuvant phase II study, Kim et al. reported 63.6% major pathologic response and 36.3% complete response rates with pembrolizumab, GX-188E, and GX-I7 in 11 resectable HPV+ patients [10]. Leidner et al. observed 33.3% downstaging and 83.3% two-year recurrence-free survival in six HPV-negative patients treated with Tri-Ad5 plus bintrafusp alfa [11].

Conclusions:

Vaccine–ICI combinations in HNSCC are safe and immunologically active but show inconsistent efficacy. The most encouraging results appear in HPV-positive and neoadjuvant settings, warranting larger biomarker-driven trials.

Epstein–Barr Virus (EBV) is a prevalent oncogenic herpesvirus associated with infectious mononucleosis, several malignancies, and autoimmune diseases, yet no licensed vaccine exists despite decades of research. Liposomes, due to their biocompatibility, biodegradability, and ability to protect antigens, are attractive platforms for EBV vaccine delivery. In this study, a gp350-based subunit vaccine was designed using liposomal carriers adjuvanted with Monophosphoryl Lipid A (MPLA).

Different lipid compositions were used to prepare multiple vaccine formulations, which were systematically compared for physicochemical stability and performance. The formulations were characterized in terms of particle size, polydispersity index, SPAN, zeta potential, encapsulation efficiency, and in vitro antigen release profile. Through sequential evaluation, suboptimal candidates were eliminated, and further studies were conducted with the most promising formulations. The selected candidate demonstrated high encapsulation efficiency (>90%) along with favorable stability characteristics. Safety was confirmed by MTT assays in L929 fibroblasts and EBV-positive Daudi cells, where both empty and antigen-loaded liposomes exhibited acceptable cytocompatibility. Safety was confirmed by MTT assays in L929 fibroblasts and EBV-positive Daudi cells, where both empty and antigen-loaded liposomes exhibited acceptable cytocompatibility. Immunological activity was assessed in THP-1 monocyte-derived cells, demonstrating that the optimized formulation induced a balanced but effective cytokine profile, characterized by significant upregulation of TNF-α and IL-6, and moderate IL-10 expression.

In addition, ongoing analyses, including ROS generation and DNA damage evaluation using the Comet assay, are expected to provide further insights into oxidative stress responses and genomic safety. Together, these findings demonstrate that the optimized gp350-loaded, MPLA-adjuvanted liposomal formulation combines nanoscale stability, favorable safety, and robust immunostimulatory activity, highlighting its potential as a promising next-generation EBV vaccine candidate.

The authors wish to thank Hacettepe University Scientific Research Projects Coordination Unit for supporting this study as part of a Master’s Thesis Project (Project No: TYL-2024-21421)