Swine coronaviruses (SeCoV) have become a major concern in pig farming and have caused enormous economic losses all over the world. Porcine deltacoronavirus (PDCoV) is a newly emerged SeCoV, which was able to infect avians as well as humans. Therefore, developing efficient vaccines against PDCoV is not only important to pork production, but also contributes to public healthcare. In this study, we identified a new PDCoV strain, CHN/GD/2023, which was isolated from a diarrheal piglet colon. After a thorough sequence analysis of the Spike gene, CHN/GD/2023 was found to be closely related with other PDCoV viruses that have recently been isolated in China. Next, a VLP-based vaccine candidate, AP205-RBD, was produced by genetically fusing the receptor-binding domain (RBD) of CHN/GD/2023 to the C-terminus of the AP205 gene. The purified AP205-RBD successfully displayed RBD on the surface and exhibited a spherical particle structure with a diameter of 51 nm. The agarose gel image demonstrated that ssRNA from E. coli was packaged inside the AP205-RBD particle. In addition, AP205-RBD demonstrated potent immunogenicity in mice, as highly RBD-specific IgG titers were detected. Importantly, these antibodies were able to neutralize CHN/GD/2023 PDCoV in vitro, suggesting that the AP205-RBD vaccine is capable of protecting against viruses. Moreover, we surprisingly found that AP205-RBD elicited antibodies that could neutralize another strain of PDCoV that was previously isolated in China, implying that AP205-RBD could potentially protect animals from different PDCoV strains. In summary, a new PDCoV strain was isolated and identified in this study, and an effective vaccine candidate, AP205-RBD, was reported, which could induce broad antibody protection responses in mice.

Introduction: Immunosenescence significantly reduces the efficacy of influenza vaccines in the elderly. This study explores the use of a clinically approved CpG 1018 adjuvant, an oligonucleotide-based adjuvant, to enhance influenza vaccine-induced immune responses to the influenza vaccine in aged mice, approximating the response in humans in their late 50s to early 60s.

Methods: Aged and young adult mice were immunized with the 2009 H1N1 pandemic influenza vaccine, with and without the CpG 1018 adjuvant. Serum antibody titers and cellular immune responses were evaluated. Mice were challenged with a lethal dose of mouse-adapted homologous viruses to evaluate the protective efficacy.

Results: In aged mice, CpG 1018 significantly increased influenza vaccine-induced serum antibody titers and Th1-biased CD4+ T cell responses and stimulated cytotoxic T lymphocytes. The CpG 1018-adjuvanted aged mice exhibited improved survival and reduced morbidity after the viral challenges as compared to those vaccinated without the adjuvant. In comparison, the non-adjuvanted vaccine induced more potent immune responses in the young adult mice.

Conclusions: Our data support the addition of CpG 1018 to influenza vaccines to enhance its immunogenicity and protective efficacy in aged mice. These findings advocate for the use of the CpG 1018 adjuvant in influenza vaccines for the elderly to enhance both humoral and cellular immune responses, thereby improving health outcomes in this vulnerable population.

Background: Little is known about the impact of COVID-19, influenza, and pneumococcus vaccinal status on hospital stays in patients admitted to internal medicine units during and after the COVID-19 pandemic.

Methods: Data on adult patients admitted to the internal medicine division (99% from the emergency care unit), Regional Hospital, Bari, Italy, between June 2020 and December 2023 were extracted from the hospital information system. Vaccine status, medical history, demographic data, and clinical outcomes were analyzed using a multiple linear regression model to determine the factors influencing the length of hospitalization.

Results: A total of2,008 patients were included (F/M = 767/1241; mean age = 73.5±SEM0.3 yrs). Overall, their mean hospital stay was 10±0.2 days and was similar between sexes. The prevalence of patients vaccinated against COVID-19 was 82.6% (doses 1, 2, 3, 4, and 5, respectively = 2.4%, 14.4%, 43.3%, 17.8%, and 4.8%); against influenza, it was 69.6% (doses 1, 2, 3, 4, and 5, respectively = 16.0%, 14.2%, 13.7%, 13.8%, and 11.9%); and against pneumococcus, this was 14.2% (doses 1 and 2, respectively = 12.1% and 2.1%), with no gender difference. The hospital stays before and after any vaccine dose were comparable. Multiple linear regression showed that among all factors (age, sex, and vaccine type and doses), only age was positively correlated with hospital stay (R² 0.04, P= 0.01). The prevalence of patients admitted for severe non-COVID-19 pneumonitis was 4.7%, and those vaccinated against COVID-19 had a shorter average hospital stay than unvaccinated patients (8.7 vs 11.3 days, P=0.03).

Conclusions: Vaccinations are preventive tools for decreasing hospital stays in internal medicine wards. COVID-19 vaccination effectively reduces the hospital stay of patients with severe (non-COVID-19) pneumonitis.

Increased COVID-19-specific secretary IgA antibody levels in the respiratory tract are required for inhibiting early COVID-19 virion particle attachment to ACE-2 receptors and primary virus replication. Because all COVID-19 vaccines are administered parenterally, it has been thought that the vaccine might not elicit sufficient mucosal immunity (1). The purpose of this study was to determine the level of IgA antibodies in respiratory samples from vaccinees. Twenty-ninenasopharyngeal swabs were collected from healthy participants who had received at least two doses of a different COVID-19 vaccination. Rt-PCR confirmed that all samples were negative for COVID-19. A quantitative ELISA kit with defined calibrators (0-25) ng/ml coated with recombinant 2019-nCoV Spike protein (antigen) was used to measure IgA antibody concentrations per sample. The results revealed that COVID-19 spike IgA was present at a lower level in the majority of the samples (86.2%), with a mean IgA level of 0.01 ng/ml. Only four samples had higher IgA levels, which accounted for 13.8%. (Fig. 1). Three subjects had elevated IgA levels, ranging from 0.5 to 1.5 ng/m. One individual had a boosted IgA level of 3.4 ng/ml, which retested negative in COVID-19 Rt-PCR and appeared to be a recently recovered asymptomatic COVID-19case. The result explains why COVID-19 vaccines failed to prevent virus transmission and infection, because the vaccines failed to elicit protective mucosal immunity in the form of highly protective secretary IgA antibodies in vaccinees. This is because the current COVID-19 vaccines are administered parentally rather than through the mucosal portal via oral immunization or nasal spray delivery. Thus, there is a need for second or third mucosal (nasal/oral) COVID-19 vaccine doses which might imitate natural infection by boosting mucosal IgA levels. This would help in reducing the number of healthy carriers and, in the long run, in eradicating the existing circulating virus.

Although vaccines against porcine epidemic diarrhea viruses (PEDVs) are available, PED outbreaks still occur in many countries due to the emergence of new variants. Therefore, more work is required to develop efficient and broadly protective vaccines. To this end, we present here a new vaccine candidate, AP205-S1, which could effectively elicit systemic and mucosal antibody responses in mice and pigs. The vaccine was generated by coupling the S1 protein of PEDV-KB2013-130 with AP205-VLP via SpyCatcher/SpyTag bonding. AP205-S1 demonstrated an intact and homogenous viral particle structure and packed ssRNA. Upon administration in mice, AP205-S1 induced high amounts of S1-specific IgG antibodies in sera as well as in gastrointestinal tracts, especially after the booster. Importantly, these antibodies were able to neutralize PEDV KB2013-130 in vitro, indicating that the vaccine protects against PEDV infection. Of note, AP205-S1-elicited antibodies exhibited cross-neutralizing potencies against AH-2018 strains, belonging to the G-I group. Last but not least, S1-specific IgG antibodies were stimulated in pigs after AP205-S1 immunization, which could recognize and block PEDV from infecting Vero cells in vitro. The viral loads in AP205-S1-immunized pigs were strikingly reduced compared to AP205-SpyCatcher-immunized pigs. In conclusion, AP205-S1 exhibited excellent immunogenicity in mice and pigs and posed protection against PEDV infection in pigs.

Introduction: Viral, bacterial, fungal, and nematode infections can cause significant losses and damage to crops. Treatment options remain limited in agriculture. Accordingly, novel immune activators are required to strengthen plant defense systems and enhance protection against pathogens. Virus-like nanoparticles (VLPs) have been extensively used in developing prophylactic and therapeutic vaccines in animals and humans. However, their potential use in plants is scarce. Hence, they may serve as a promising candidate for novel agricultural solutions and for advancing plant nanotechnology.

Methods: We synthesized protein-based VLPs derived from the bacteriophage Qβ-VLPs encapsulating non-replicative ssRNA. We fluorescently labeled Qβ-VLPs for visualization in Nicotiana benthamiana plants utilizing confocal microscopy. To assess the potential of our nanoparticles to induce an immune response in treated plants, we evaluated the upregulation of the key genes responsible for leaf defense mechanisms against pathogens.

Results: We demonstrate that the fluorescence of the icosahedral 30 nm Qβ-VLPs can be effectively visualized within the intercellular space of (N. benthamiana) one hour post infiltration. Furthermore, infiltration with Qβ-VLPs led to an upregulation in key defense genes (NbPR1a, NbPR5, NbNPR, NbERF1, NbMYC2, and NbLRR2) in treated plants. Using RT-qPCR, a significant increase in the relative expression levels of defense genes was observed, with sustained high levels of NbERF1 and NbLRR2 even after 24 h. Taken together, the data suggest that Qβ-VLPs have a significant capacity to upregulate genes pivotal to leaf defense mechanisms against pathogens in N. benthamiana plants.

Conclusion: We conclude that the dispersal of our protein-based nanoparticles in the intercellular space of N. benthamiana leaves, loaded with ssRNA, initiates a PAMP-triggered immunity. This activation launched a series of signaling cascades, culminating in the enhanced expression of genes associated with various defense mechanisms.

Over the past few decades, dengue fever has become a significant threat to global health, mainly in tropical regions but more lately also in regions with moderate climates. Since the currently approved vaccines have significant practical limitations, there is a strong need for a dengue vaccine that is safer and more effective. In this study, we introduce novel vaccination candidates covering all four Dengue virus (DENV) Serotypes based on virus-like particles (VLPs). VLPs are traditional vaccine platforms which are already implemented on the market for several diseases. They are considered safe and efficient because they have a highly organized and repetitive surface and lack any replication-competent genetic material. Due to the high thermostability of VLPs used here, distribution and administration in DENV endemic zones would be simplified and facilitate vaccination programs. To design such vaccine candidates, the Dengue virus envelope protein domain III (DV) of the serotypes 1, 2, 3, or 4, which represents the major target of DENV-neutralizing antibodies, was selected to be either genetically fused or chemically coupled to bacteriophage-derived AP205-VLPs. To facilitate the incorporation of the relatively large EDIII domain, AP205 monomers were dimerized, resulting in a VLP with 90 rather than 180 N- and C-termini. The generated vaccines induced high antibody titers of high affinity/avidity in mice, indicating a protective potential of the vaccine candidates. This was confirmed by the ability to neutralize the different Dengue virus serotypes in an in vitro neutralization assay. The administration of a tetravalent vaccine simultaneously induced high neutralizing titers against all four serotypes. Importantly, no enhancing antibodies were induced, at least not against the tested DENV2. In conclusion, the vaccine candidates, especially when administered in a combined fashion, exhibit intriguing properties for potential use in the field, and exploring the possibility of conducting a clinical trial would be a logical next step.

Hepatocellular carcinoma (HCC) is becoming more prevalent, making it one of the most serious worldwide health challenges. Several studies have focused on designing effective multi-epitope peptide vaccines against HCC in recent years. An in silico approach was used in prior investigations to create a multi-epitope peptide vaccine against HCC. Glypican-3 (GPC-3), melanoma-associated antigen-C2 (MAGE-C2), aspartyl-β-hydroxylase (ASPH), and New York esophageal squamous cell carcinoma 1 (NY-ESO-1) are four overexpressed antigens in HCC patients that we used in the vaccine's design. A multi-epitope peptide vaccine against HCC was designed through in silico antigen selection, physicochemical characterization, epitope prediction, structural analysis, cloning optimization, immune simulation, bacterial expression, protein purification, and immunological evaluation in rats. Four B-cells, nine MHC-I restricted, and eleven MHC-II restricted epitopes were selected based on their antigenicity score >0.5 and non-allergenicity with an adjuvant that included a segment of the microbial heat shock protein (HSP70) peptide 407-426 for vaccine construction. The relevant linkers were used to link each of the vaccine components and the cloned-in vector. This vector was successfully transformed into the Escherichia coli strain to further evaluate itsimmunological response and efficacy. The primary aim of this study is to design a vaccine and subsequently conduct laboratory experiments to evaluate its efficacy and safety profiles. It covers 90% of the global population, hence it is very effective. The vaccine's easily soluble nature was shown by its physicochemical properties, such as its hydropathicity index (-0.457) and aliphatic index (75.63). The vaccine has a high probability of being soluble in E. coli, with a solubility of 0.680. The ongoing results will provide insights into the efficacy of the vaccine against HCC.

Artificial intelligence (AI) has become a game-changer in advancing mRNA vaccine development, bringing unparalleled speed and efficiency to research. AI-driven tools play a crucial role in enhancing vaccine potency and stability by optimizing gene sequences. This results in vaccines that provoke stronger immune responses and are more resistant to degradation. Such progress could enhance health equity and global vaccine distribution, especially in areas lacking adequate cold storage facilities. However, integrating AI into vaccine development poses several technical, ethical and regulatory challenges. One significant hurdle is accurately identifying antigens that can trigger effective immune responses. Additionally, the swift pace of AI-driven research often surpasses current regulatory frameworks, necessitating a delicate balance between innovation and oversight. Ethical issues such as data privacy, algorithmic bias, safety, explainability and transparency in decision-making processes must be tackled to maintain public trust. Regulatory agencies are addressing these obstacles by formulating guidelines covering data authenticity, reliability, transparency,and real-world patient monitoring. A risk-based AI regulation approach is being explored, requiring robust governance structures and collaborative efforts among global regulatory bodies. While AI shows great potential in transforming mRNA vaccine development, concerted efforts are crucial to navigate challenges and ensure the safe and equitable realization of its benefits worldwide.

Introduction: Chicken astrovirus (CAstV) is a ubiquitous agent infecting global broiler production, mainly affecting embryos and neonates, with some highly pathogenic (hp) strains causing hatchery losses (up to 69%) and fatal kidney disease with visceral gout. There are two serogroups of CAstV, A and B; most diseases have been associated with the B serogroup, which is subdivided into subgroups via capsid gene genotyping.

Methods: The CAstV-11672 (subgroup Bi) strain was administered to in-lay broiler breeder hens as a live breeder vaccine candidate. Sera were monitored weekly for seroconversion via ELISA. Eggs were collected from seroconverted and control hens, and were synchronised and incubated to hatch. Hatchlings in isolators were challenged with one of three hp strains belonging to subgroups Bi, Biii and Biv. The chicks were visually monitored for disease development; their CAstV levels were monitored by real time RT-qPCR; and their weight and development of kidney lesions by days four and ten (termination) were monitored.

Results: Thelevels of CAstV seroconversion in hens were low after oral inoculation but increased significantly after intramuscular inoculation. The levels of anti-CAstV antibodies detected in egg yolks were approximately half that of the hens. The weights of chicks with maternally-derived antibodies (matABs) were significantly higher at day 10 after being challenged with hp strains from the Bi and Biii subgroups. The chicks with matABs showed no kidney lesions at day 4 from any of the hp strains, whereas the chicks without matABs had substantial numbersof kidney lesions at day 4, which were statistically significant by day 10.

Conclusions: The CAstV-11672 strain elicited a strong immune response in adult birds, with successful the transmission of matABs that protected the hatchlings from challenges with hp strains of CAstV, resulting in the prevention of kidney damage and higher body mass compared to chicks without anti-CAstV matABs. CAstV-11672 appears to be a successful candidate for a CAstV breeder vaccine.