Clinical and Experimental Vaccine Research最新文献

Purpose: Hepatitis A virus (HAV) production has been limited by its slow replication rate and reliance on diploid cell lines like MRC-5, which present challenges in scalability, passage limitations, and serum-free culture conditions. This study aimed to develop an HAV vaccine strain with enhanced replication capacity.

Materials and methods: We generated a reverse genetically modified HAV vaccine strain (RG-HAV) and adapted it to Vero cells through sequential culturing. Replication rates of RG-HAV and a commercially used strain, HM-175, were compared in Vero and MRC-5 cells. Nucleotide sequences, including coding and non-coding regions like the internal ribosomal entry site (IRES), were analyzed. Structural assessments included 3-dimensional modeling of IRES and relative codon deoptimization analysis of the capsid. Immunogenicity was evaluated by measuring HAV-specific antibody responses in mice.

Results: Vero-adapted RG-HAV achieved a 30-fold increase in production yield compared to initial transfection. In Vero cells, RG-HAV peaked at 15 days post-infection, compared to 20 days for HM-175. In MRC-5 cells, RG-HAV and HM-175 reached peak production at 10 and 15 days, respectively. RG-HAV produced over 5-fold more HAV in Vero cells and 8-fold more in MRC-5 cells than HM-175. Sequence analysis revealed nine amino acid differences in RG-HAV structural proteins and five nucleotide changes in the type III IRES region, potentially enhancing IRES functionality. Immunization with inactivated RG-HAV with alum hydroxide induced HAV-specific antibody responses in mice.

Conclusion: RG-HAV offers enhanced replication and production yields, supporting its potential in advancing HAV vaccine development.

Purpose: Benign prostatic hyperplasia (BPH) is a common condition in men that can impact quality of life, especially in older age. BPH is nonmalignant prostate enlargement associated with lower urinary tract symptoms (LUTS). Various factors like aging, hormonal imbalance, and inflammation contribute to BPH, with androgen dysregulation playing a key role. The coronavirus disease 2019 (COVID-19) pandemic raised concerns about vaccine side effects, particularly in BPH patients experiencing LUTS. Research is ongoing to understand the impact of COVID-19 vaccination on LUTS in BPH patients.

Materials and methods: This prospective longitudinal study conducted at Sina Hospital in Tehran, Iran, from September 2022 to March 2023 enrolled 106 BPH patients receiving COVID-19 vaccines. Ultrasonography, total and free prostate specific antigen (PSA) test, and urine analysis were performed, and International Prostate Symptom Score questionnaires were completed before the vaccination. Vaccines included Oxford University/AstraZeneca, Sinopharm, or Sputnik-V, with booster doses administered per manufacturer protocol. Three months post-booster shot, patients were re-evaluated with the same questionnaire. Data was analyzed using SPSS software.

Results: Out of 3,591 individuals receiving COVID-19 vaccine, 106 were eligible for analysis. The mean ± standard deviation age on vaccination day was 65.4±11.74 years. Individuals receiving COVID-19 vaccines found no significant changes in PSA levels or prostate volume post-vaccination. Among urinary symptoms, urgency, dysuria, frequency, and hematuria rates increased significantly (p-value<0.05). Other symptoms showed no statistical differences.

Conclusion: Our findings elucidate that urgency, dysuria, frequency, and hematuria may be exacerbated after COVID-19 vaccination in BPH patients.

Purpose: We evaluated the immunogenicity and safety of Rabivax-S (Pitman-Moore 3218 strain) by intramuscular (IM) and intradermal (ID) routes in Vietnam.

Materials and methods: We conducted an open-label, randomized, phase 4, single-center clinical trial in healthy individuals aged five to 60 years divided into two groups according to age (5-15 years old and 16-60 years old). They were randomized to receive 3 doses of Rabivax-S IM 1 mL) or Rabivax-S ID (0.1 mL) in 1:1 ratio on days 0, 7, and 21. Adverse events (AEs) were collected for 7 days after each dose and rabies-neutralizing antibody levels were measured were measured by RFFIT on days 0, 21 and 42.

Results: Totally 220 participants aged 5-15 years old (117 participants) and 16-60 years old (103 participants). The seroconversion rates of antibodies among the two groups (IM and ID doses) were all 100.0% on D21 and D42/42. On D21 and D42/42, the geometric mean concentration of the two groups was much higher than the immune protection level of 0.5 IU/mL. There were no AEs or serious AEs recorded in all four visits. Unsolicited AEs were reported by 3% of participants. The most common AEs during seven days after each dose were fever, pain, and erythema. Mostly mild local and systemic AEs were reported across the two groups and all resolved without sequelae.

Conclusion: The study results conclusively demonstrate that the complete regimen of both the IM and ID 3-dose series Rabivax-S was found to be clinically safe and immunogenic. After this study, Rabivax-S is now available in Vietnam and can be used for pre- and post-exposure prophylaxis.

Clinical trials registration: ClinicalTrials.gov Identifier: NCT05937113.

The Smart Vaccination System introduces a vaccine reminder framework that is SMS-based and is intended to help parents ensure that their children's vaccinations are current. Although traditional methods rely on written schedules to organize vaccination appointments, these are frequently insufficient, as busy parents may neglect critical dates. A web-based vaccine reminder application has been created to address this challenge, providing timely notifications when a child's next vaccination is due. This system streamlines the process for parents, enabling them to remain proactive, informed, and organized regarding their child's health. The application ultimately contributes to enhanced public health outcomes by increasing the probability that children will be protected against preventable diseases by reducing missed vaccinations.

Purpose: Rabies remains a significant public health concern worldwide, particularly among paediatric populations who are vulnerable to animal exposures. This prospective study aimed to assess the safety and clinical efficacy of rabies biologicals in pediatric patients following category III animal exposures.

Materials and methods: A prospective study was undertaken enrolling 289 pediatric patients fulfilling eligibility criteria who presented with category III animal exposures at the anti-rabies clinic of Kempegowda Institute of Medical Sciences Hospital and Research Centre, Bangalore. All the subjects received rabies biologicals as per National Centre for Disease Control guidelines. The details pertaining to socio-demographic profile, biting animal, characteristics of wound, and details of post-exposure prophylaxis (PEP) provided were recorded. All the study subjects were followed up for immediate and delayed adverse events (AEs). Subsequently, all were followed up for 6 months to demonstrate the clinical efficacy of PEP.

Results: The mean age of study subjects was 9.4 years, and most of them (43%) were going to school. Dog was the predominant biting animal (96.6%) with most bites being abrasions (45%), mainly on the lower limbs (42%). Single rabies monoclonal antibody was the most commonly administered passive immunization (67%), and purified Vero cell rabies vaccine was the predominant vaccine (65%). AEs following PEP were primarily local, predominantly pain (13.2%), and there were no systemic events. All the subjects were alive and healthy at the end of 6 months following PEP.

Conclusion: This study contributes valuable insights into the safety and clinical efficacy of rabies biologicals in a pediatric cohort following category III animal exposures, supporting the continued use of these biologicals in pediatric patients.

Purpose: Despite scientific evidence and recommendations for healthcare workers (HCWs), influenza vaccination coverage rates (VCRs) are quite low. An interdisciplinary team-led quality improvement project was planned to identify the root causes of low influenza VCR among nurses.

Materials and methods: To reveal the current situation, the influenza vaccination process flow chart for HCWs in the hospital and influenza VCRs of nurses in 4 influenza seasons between 2018 and 2023 were determined. A survey, including the Health Belief Model Scale for Influenza Prevention, was applied to determine nurses' attitudes towards vaccination and the barriers and facilitators of vaccination. Possible reasons for low VCRs were listed using brainstorming and placed in a fishbone diagram. The nominal group technique was used to score these potential causes, leading to identifying the root causes.

Results: VCR among nurses ranged from 7.1% to 17.7%, one in 3 nurses vaccinated by mobile teams. Major root causes of low VCRs were identified as inappropriate prioritization policy of the Ministry of Health in the distribution of seasonal influenza vaccines, lack of continuity of supply afterward, lack of vaccination culture, and effective communication strategies to motivate vaccination.

Conclusions: Influenza VCRs among nurses are well below the recommended level. The most important reasons for low VCRs are the lack of effective influenza vaccination policies at the institutional and national level, lack of awareness of the demand for mobile vaccination, and uncertainty in vaccine supply. Securing the availability and accessibility of vaccines on-site might be the most important strategy for improving VCRs.

Purpose: Calcium phosphate (CaP) and iron oxide (IO) nanoparticles (NPs) are promising adjuvants and delivery systems for vaccination. Furthermore, it has been shown that the chimeric antigen TF/Bp26/Omp31 (TBO) is a good candidate for stimulating protection against virulent Brucella melitensis. Our aim in the present study was to compare the roles of CaP and IO NPs for induction of the immune response and protection against B. melitensis 16M by using the TBO antigen as a model protein.

Materials and methods: The tbo gene was expressed in the bacterial host and was evaluated by SDS-PAGE and western blot. The recombinant TBO was loaded onto CaP (CaP/TBO) and IO (IO/TBO) NPs. CaP/TBO and IO/TBO NPs were administered subcutaneously.

Results: Antibody levels showed that immunization with both CaP/TBO and IO/TBO NPs stimulated mixed Th1-Th2 immune responses. In addition, immunized mice were challenged with a virulent strain of B. melitensis 16M. Immunized mice with CaP/TBO NPs showed a higher degree of protection than vaccinated animals with IO/TBO NPs.

Conclusion: Altogether, our results indicated that the CaP NPs are a potent adjuvant and delivery system for subcutaneously administered Brucella antigens.

Purpose: Influenza virus remains a serious burden to global public health. Current influenza vaccine fails to provide impeccable protection efficacy to the annual seasonal influenza and cannot offer a timely response to potential pandemic influenza. It is necessary to develop next generation influenza vaccines to solve the current dilemma.

Materials and methods: We developed a recombinant, self-assembling ferritin nanoparticle that presents the extracellular domain of the influenza hemagglutinin antigen on its surface, designated as ferritin-HA. After characterizing its structure and properties, we evaluated its capacity to trigger an immune response and offer protection against influenza virus challenge in a mouse model.

Results: The recombinant ferritin-HA protein expressed in Chinese hamster ovary cells assembles into nanoparticles of a defined size. This nanoparticle vaccine enhances the uptake efficiency of Dendritic cells and promotes their maturation. Immunization with ferritin-HA nanoparticle in mice induced high levels of immunoglobulin G, hemagglutination inhibition antibodies, and microneutralization antibodies, demonstrating their stronger immunogenicity compared to current split virion vaccines. Additionally, ferritin-HA nanoparticle conferred well protection against a lethal challenge with a heterologous H3N2 influenza virus in mice.

Conclusion: This study indicates that a self-assembling ferritin-HA nanoparticle has great potential for enhancing immune response and protective efficacy in mice, presenting a promising strategy for developing next generation influenza vaccine candidate.

Purpose: Vaccination of athletes is an effective preventive intervention to maintain athletic performance. Data reporting the vaccination status of elite athletes are limited. Aim of this study was to provide an overview about the vaccination status in elite athletes who were affiliated to the German Armed Forces.

Materials and methods: Six hundred seventy athletes were included in this retrospective cross-sectional study. Statistical analysis was performed using McNemar's test, φ coefficient and logistic regression.

Results: The 0.3% of all included athletes had a complete vaccination status as recommended by the German Standing Commission on Vaccination when they started their career. Regarding the different kinds of vaccination, there was a range from 3.0% (influenza) to 69.6% (mumps, measles, rubella). Although a valid vaccination status is mandatory for soldiers, only 6.3% of the athletes had a valid one at the time of data collection. During the observation period, only few athletes worsened their vaccination status. Specific differences could be seen for different kinds of sports. Swimmers and sleigh drivers were almost completely below average. The vaccination status among Taekwondo Fighters and Fencers were almost entirely above average. Worse vaccination status was found for vaccinations that required more frequent repetition. The vaccination status was comparable for vaccinations that are available as combination vaccines.

Conclusion: Although a complete vaccination status was mandatory, there were vaccination gaps. It seems necessary to be more stringent in the prevention of vaccination gaps. Athletes, physicians, and sports associations should cooperate to find an effective way to get optimum prevention.

Purpose: Due to the widespread distribution and importance of Toxoplasma gondii infection as a parasitic zoonosis, multi-epitope vaccine design was implemented using a set of immunodominant epitopes screened out of a wide scope of membrane proteins.

Materials and methods: On this basis, 5 vaccine candidates were created using linkers ([GGGGS]₂, KK, AAY, GPGPG, GDGDG, EAAAK) and adjuvants (RS-09 peptide, Mycobacterium tuberculosis resuscitation-promoting factor E [RpfE] and 50S ribosomal protein, human interferon [IFN]-γ).

Results: Polytopes with RS-09 alone (Toxo-App) and with IFN-γ (Toxo-Apfn), and one with 50S ribosomal protein (Toxo-Ribos) showed the highest immunogenicity during in silico prediction, and their 3-dimensional structure was refined. Protein-protein docking and molecular dynamics simulation analysis was done between the Toxo-App and human toll-like receptor (TLR)-4, rendering a stable connection. Codon optimization and in silico cloning was done ultimately for the selected vaccine candidate.

Conclusion: In conclusion, potent multi-epitope vaccine candidates were designed against toxoplasmosis using a diverse set of in silico techniques, while further wet experiments are recommended.