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.