Vaccines

Background/Objectives: Aged care residents are highly vulnerable to vaccine-preventable diseases. Despite recommendations and funding under Australian programs, vaccination rates among residents for COVID-19, influenza, pneumococcal and shingles remain sub-optimal. The aim of this work was to assess if tailored quality improvement interventions would improve vaccination coverage in aged care residents. Methods: This was a quality improvement initiative evaluated using a quasi-experimental pre–post design. Building on previously identified barriers and enablers, a package of interventions and resources was developed to support consent processes, vaccination planning, and tracking. Pre- and post-intervention vaccination coverage was assessed using resident lists from participating aged care facilities and data extracted from the Australian Immunisation Register (AIR) at two time points, 14 months apart. A process evaluation survey was distributed to RACF staff. Results: Of the 6964 residents listed, 5153 (74%) remained registered in AIR when data was extracted post-intervention. Shingles showed the greatest improvement in absolute difference (+23.4%), followed by pneumococcal (+14.2%) and influenza (+10.9%), despite a high baseline of 68.5%. COVID-19 coverage declined by 7.4% when applying a 6-month reporting interval. Twenty-five staff completed the process evaluation survey; 45% of respondents identified discrepancies between AIR data and internal records, indicating underreporting by external providers. Interventions including the consent template and vaccination tracker were reported as useful and were used to support local vaccination. Conclusions: This quality improvement initiative improved coverage for three of the four recommended and funded vaccines for RACF residents and demonstrated the value of tailored interventions informed by consumer and provider feedback. The approach potentially offers a scalable model for improving vaccination rates in aged care across Australia.

Background: Highly potent vaccines are essential for the effective control of classical swine fever (CSF). Since CSF re-emerged in 2018 in Japan, the live CSF virus (CSFV) vaccine—a guinea pig exaltation of Newcastle disease virus-negative strain vaccine (GPE⁻, genotype 1.1)—has been applied to domestic pigs, contributing to a reduction in outbreaks. Meanwhile, the persistence and continued expansion of CSFV in wild boar populations have raised concerns regarding potential antigenic divergence. Methods: We systematically evaluated the neutralizing reactivity of sera from GPE⁻-vaccinated pigs against CSFV strains (genotype 2.1) recently circulating in Japan against identified a representative strain that showed markedly reduced neutralization. We directly assessed the protective efficacy of the GPE⁻ vaccine against this strain in a controlled challenge experiment. At 4 weeks post-vaccination, both vaccinated and unvaccinated pigs were orally challenged with the representative Japanese strain and monitored for 3 weeks thereafter. Results: Among the Japanese CSFV strains, the JPN/SM/WB/2022 isolate exhibited markedly reduced neutralizing reactivity—over 32-fold lower than that against the vaccine strain—when tested with GPE⁻ vaccine-induced antisera. In the experimental infection in pigs, unvaccinated pigs exhibited typical clinical signs of CSF and viremia, and two pigs reached the humane endpoint. In contrast, none of the vaccinated pigs showed any clinical signs of infection. Robust humoral and cellular immune responses were induced in vaccinated pigs, which may correlate with the observed complete protection. Conclusions: The GPE^– live vaccine provides protective immunity against an antigenically distinct strain, prevents disease, and limits viral spread in domestic pigs.

Objectives: In response to the challenge that Staphylococcus aureus (S. aureus) vaccines fail to induce durable protective immunity, this study aims to develop a novel antigen-adjuvant co-design strategy. Specifically, we rationally combined the immunodominant toxin antigen LukS-PV with the immunologically subdominant adhesin antigen ClfA, co-delivered via the PLGA-PEG nanoadjuvant system, to elicit synergistic, durable, and balanced humoral and cellular immune responses. Methods: Firstly, recombinant antigens LukS-PV and ClfA were individually covalently conjugated to PLGA-PEG 25% nanoparticles (25% NPs) using EDC/NHS chemical coupling to construct a combined nanovaccine, followed by systemic safety verification in a mouse model. Subsequently, specific antibody titers were detected by ELISA, and the secretion levels of IL-4, IFN-γ, and IL-17A were measured by ELISPOT assay to comprehensively evaluate the humoral and cellular immune responses induced by the vaccine. Finally, the protective efficacy of the vaccine was assessed through acute and long-term (up to 180 days) lethal challenge experiments, thereby verifying the effectiveness of this co-design strategy based on rational antigen selection. Results: The combined vaccine group (25% NPs-rClfA + 25% NPs-rLukS-PV) not only elicited high levels of specific antibodies but, more importantly, induced robust cellular immune responses dominated by Th1 and Th17 cells. Challenge experiments confirmed that the protective efficacy of the combined vaccine was significantly superior to that of any single-antigen vaccine and provided complete protection for up to 180 days. Crucially, the same antigen combination formulated with a traditional aluminum adjuvant failed to confer this durable protection, underscoring the essential role of adjuvant synergy. Conclusions: This study demonstrates that rational combination of immunodominant and subdominant antigens with a compatible nanoadjuvant induces synergistic and durable immunity against S. aureus. This co-design strategy addresses key limitations of previous vaccines and provides a promising foundation for future clinical development.