Potential Vaccine Research Articles

Development and evaluation of a novel E7 multi-epitopic vaccine for human papillomavirus type 16: design, expression, purification, and immunological characterization

BackgroundPersistent infection with high-risk Human papillomavirus (HPV), specifically HPV-16, is the leading cause of cervical cancer. Although preventative vaccines have shown significant efficacy in preventing HPV infection, cervical cancer is a significant public health issue that affects millions of women worldwide. Modern therapeutic approaches, such as peptide vaccines, could be promising and have potential for the treatment of the HPV-infected population.MethodsA HPV16-E7 multi-epitopic vaccine (MEVE7) was designed to comprise potent CD4 + and CD8 + T cell epitopes and optimally expressed in a prokaryotic expression system. Polyclonal antibodies were generated, and their reactivity with immunizing antigen and native protein in E7 expressing cells (TC-1) was assessed by ELISA and immunofluorescent staining, respectively. The efficacy of the vaccine was assessed in a therapeutic animal model of HPV-induced cancer.ResultsOur study revealed that the final construct was successfully expressed in E. coli BL21 (DE3)-gold within 4 h of induction as inclusion bodies. Among the tested solubilization buffers, the buffer with a pH of 12 and containing 2 M urea showed the highest solubilization effect. Polyclonal antibodies directed against the E7 multi-epitope vaccine were able to react strongly with the immunizing antigen and E7-bearing cells (TC-1). Immunization of TC-1 tumor-bearing mice with HPV16-E7, markedly delayed tumor growth and propagation.ConclusionThe poly-epitope vaccine for HPV16-E7, as expressed and purified in this research, is highly immunogenic and capable of triggering E7-specific antibodies, making it a potential therapeutic HPV vaccine. Further research is needed to optimize the vaccination schedule and assess the E7-specific immune cell profile.

The development of opioid vaccines as a novel strategy for the treatment of opioid use disorder and overdose prevention.

Opioid use disorder (OUD) affects over 40 million people worldwide, creating significant social and economic burdens. Medication for opioid use disorder (MOUD) is often considered the primary treatment approach for OUD. MOUD, including methadone, buprenorphine, and naltrexone, is effective for some, but its benefits may be limited by poor adherence to treatment recommendations. Immunopharmacotherapy offers an innovative approach by using vaccines to generate antibodies that neutralize opioids, blocking them from crossing the blood-brain barrier and reducing their psychoactive effects. To date, only 3 clinical trials for opioid vaccines have been published. While these studies demonstrated the potential of opioid vaccines for relapse prevention, there is currently no standardized protocol for evaluating their effectiveness. We have reviewed recent preclinical studies that demonstrated the efficacy of vaccines targeting opioids, including heroin, morphine, oxycodone, hydrocodone, and fentanyl. These studies showed that vaccines against opioids reduced drug reinforcement, decreased opioid-induced antinociception, and increased survival rates against lethal opioid doses. These studies also demonstrated the importance of vaccine formulation and the use of adjuvants in enhancing antibody production and specificity. Finally, we highlighted the strengths and concerns associated with the opioid vaccine treatment, including ethical considerations.

An XBB.1.5-based inactivated SARS-CoV-2 vaccine partially protects against XBB.1.5 and JN.1 strains in hamsters

The SARS-CoV-2 Omicron BA.2.86 variant and its descendant lineages, including JN.1, are rapidly spreading and becoming dominant globally. Vaccination is an essential primary preventative measure. While mRNA vaccines have been widely used worldwide, it is essential that we continue to prepare alternative vaccine modalities. Consistent with WHO recommendations, we developed an inactivated Omicron XBB.1.5 vaccine and assessed its efficacy against XBB.1.5 and JN.1 strains. Immunization with the inactivated XBB.1.5 vaccine induced antigen-specific antibodies leading to protection from XBB.1.5 and antigenically distinct JN.1 strains in a hamster model. In addition, we found that immunization reduced viral replication in hamster respiratory organs, suggesting protection against XBB.1.5 and JN.1 variants. Our findings highlight the potential of inactivated vaccines against evolving SARS-CoV-2 variants.

Anti-Ebola virus mAb 3A6 protects highly viremic animals from fatal outcome via binding GP(1,2) in a position elevated from the virion membrane

Monoclonal antibodies (mAbs) against Ebola virus (EBOV) glycoprotein (GP1,2) are the standard of care for Ebola virus disease (EVD). Anti-GP1,2 mAbs targeting the stalk and membrane proximal external region (MPER) potently neutralize EBOV in vitro and are protective in a mouse model of EVD. However, their neutralization mechanism is poorly understood because they target a GP1,2 epitope that has evaded structural characterization. Using X-ray crystallography and cryo-electron tomography of mAb 3A6 complexed with its stalk–MPER epitope, we reveal a previously undescribed mechanism in which 3A6 binds to a conformation of GP1,2 that is lifted from the virion membrane. We further show that in both domestic guinea pig and rhesus monkey EVD models, 3A6 provides therapeutic benefit at high-viremia advanced disease stages and at the lowest dose yet demonstrated for any anti-EBOV mAb-based monotherapy. The findings reported here can guide design of next-generation highly potent anti-EBOV therapeutics and vaccines.

Diversifying T-cell responses: safeguarding against pandemic influenza with mosaic nucleoprotein.

The World Health Organization (WHO) estimates that seasonal influenza causes 3-5 million cases of severe illness annually. The influenza virus frequently undergoes genetic changes through antigenic drift and antigenic shift, resulting in annual epidemics and occasional pandemics. Consequently, a major public health objective is to develop a universal influenza vaccine that offers broad protection against both current and pandemic influenza A strains. In this study, we designed a nucleoprotein (NP) antigen (termed mosaic NP) comprising antigenic regions found in thousands of influenza viruses, aiming to use it as a vaccine to induce broad anti-influenza T-cell responses. Our findings indicate that the mosaic NP vaccine provided significant protection against seasonal H1N1 and H3N2, as well as the pandemic H1N1 strain, demonstrating its effectiveness across various influenza subtypes. These findings suggest that the mosaic NP is a potential universal influenza vaccine antigen, capable of protecting against diverse strains of influenza viruses.

Distinct immunogenicity outcomes of DNA vaccines encoding malaria transmission-blocking vaccine target antigens Pfs230D1M and Pvs230D1.

Transmission-blocking vaccines (TBVs) targeting sexual-stage antigens represent a critical tool for malaria control and elimination through inhibiting parasite development within mosquitoes. P230, displayed on the surface of gametocytes and gametes, plays a crucial role in gamete fertilization and is one of the leading TBV candidates for both Plasmodium falciparum and P. vivax. Antibodies induced by immunization with a recombinant P. falciparum protein encompassing a portion of N-terminal prodomain and domain 1 (Pfs230D1M) have revealed strong transmission-reducing activity (TRA) in preclinical studies. While a recombinant Pvs230D1, the P. vivax homolog of Pfs230D1M, has not been evaluated in preclinical immunogenicity studies, both Pfs230D1M and Pvs230D1 are currently scheduled for evaluation in clinical trials. In this study, we developed DNA vaccines encoding Pfs230D1M and Pvs230D1 for a side-by-side comparison of their immunogenicity. Potent antibody responses were induced in mice immunized with each DNA vaccine delivered by in vivo electroporation (EP). Anti-Pfs230D1M IgG exhibited potent dose-dependent TRA in a complement-dependent manner in standard membrane feeding assays (SMFA). In contrast, anti-Pvs230D1 IgG exhibited only moderate TRA in direct membrane feeding assay (DMFA) using blood from multiple P. vivax-infected donors. Antibodies induced by the Pfs230D1M DNA vaccine revealed a strong IgG1 bias and higher avidity as compared to a balanced IgG1/IgG2 response and lower antibody avidity by the Pvs230D1 DNA vaccine. Our results demonstrate the potential of both Pfs230D1M and Pvs230D1 DNA vaccines as TBV candidates against P. falciparum and P. vivax, and provide a rationale for future optimization to enhance the efficacy of DNA vaccines based on Pfs230 and Pvs230.

Large-scale transcript variants dictate neoepitopes for cancer immunotherapy.

Precise neoepitope discovery is crucial for effective cancer therapeutic vaccines. Conventional approaches struggle to build a repertoire with sufficient immunogenic epitopes. We developed a workflow leveraging full-length ribosome-nascent chain complex-bound mRNA sequencing (FL-RNC seq) and artificial intelligence-based predictive models to accurately identify the neoepitope landscape, especially large-scale transcript variants (LSTVs) missed by short-read sequencing. In the MC38 mouse model, we identified 22 LSTV-derived neoepitopes encoded by a synthesized mRNA lipid nanoparticle vaccine. As a standalone therapy and combined with anti-PD-1 immunotherapy, the vaccine curbed tumor progression, induced robust T cell-specific immunity, and modulated the tumor microenvironment. This underscores the multifaceted potentials of LSTV-derived vaccines. Our approach expands the neoepitope source repertoire, offering a method for discovering personalized cancer vaccines applicable to a broader tumor range. The results highlight the importance of comprehensive neoepitope identification and the promise of LSTV-based vaccines for cancer immunotherapy.

Novel fusion protein REA induces robust prime protection against tuberculosis in mice.

While many novel candidates for tuberculosis vaccines are presently undergoing pre-clinical or clinical trials, none of them have been able to eliminate infection entirely. In this study, we engineered a potent chimeric protein vaccine candidate, Rv2299cD2D3-ESAT-6-Ag85B (REA), which induced Th1 and Th17 responses via dendritic cell maturation. REA-activated macrophages operated the killing mechanisms of Mycobacterium tuberculosis (MTB), such as phagosomal maturation and phagolysosome fusion, through the (PI3K)-p38 MAPK-Ca2+-NADPH oxidase pathway. Dendritic cells and macrophages activated by REA elicited synergistic anti-mycobacterial responses. Notably, REA-immunized mice suppressed MTB growth to undetectable levels at 16 weeks post-infection, which was supported by gross and pathologic findings and acid-fast staining of the lung tissues, and maintained antigen-specific multifunctional IFN-γ+IL-2+TNF-α CD4+ T and long-lasting T cells producing cytokines in the tissues. Our findings suggest that REA is an outstanding prime prophylactic vaccine candidate against tuberculosis.

P-598. Attitudes toward a potential Norovirus vaccine among patients with medically-attended acute gastroenteritis in the US

Abstract Background Clinical trials for norovirus (NoV) vaccines are underway. Prior research has found generally positive attitudes toward a potential NoV vaccine, but there is limited understanding of how the COVID-19 pandemic may have impacted attitudes toward novel vaccines. Methods We identified medically-attended acute gastroenteritis (MAAGE) encounters among Kaiser Permanente Northwest members of all ages based on ICD-10 diagnostic codes, occurring from 11/17/2023-4/18/2024. Participants were asked to complete surveys which included questions about their level of agreement with the need for and willingness to get a potential NoV, as well as whether the COVID-19 pandemic impacted attitudes about vaccines.Figure 2.How has the COVID-19 pandemic changed attitudes about vaccines? Distribution of responses, by age group, November 2023-April 2024. Results Of 8,363 adults and 666 parents/guardians of children with MAAGE who were invited to participate, 553 (6.6%) adults and 38 (5.8%) guardians consented and completed surveys. Among adults, median age was 46 (range 18-90) years; most were female (76%) and of white race (84%). Among children of parents/guardians, median age was 4 (range 0-17) years; 58% were female and 89% were white. Overall, 37% of adult MAAGE patients agreed that a NoV vaccine was needed to prevent illness for themselves and 47% agreed that a vaccine was needed to protect the community; 56% agreed that they would get a NoV vaccine if available. When stratified by age group (18-49 yrs., 50-64 yrs., 65+ yrs.), the oldest respondents had the most favorable responses, with 63% of adults 65+ years indicating that they would get a potential vaccine (Fig 1). Among guardians, 61% agreed a vaccine was needed to prevent their child from getting ill and 74% agreed the community was in need of a NoV vaccine. Overall, 68% agreed they would vaccinate their child. When asked how the COVID-19 pandemic had impacted attitudes about vaccines, most respondents indicated there was either no change (37-42%) or they had increasingly positive attitudes (26-41%); a minority (6-16%) reported more negative attitudes (Fig 2). Conclusion In this sample of patients with recent MAAGE events, over 60% of adults 65+ and child guardians expressed willingness to get a NoV vaccine for themselves or their child. More respondents reported a positive shift in comparison to a negative shift in attitude towards vaccines following the COVID-19 pandemic. Disclosures Holly C. Groom, MPH, Hillevax: Grant/Research Support|Moderna: Grant/Research Support Matthew T. Slaughter, MS, Moderna: Grant/Research Support Judy L. Donald, MA, HilleVax: Grant/Research Support|Janssen: Grant/Research Support|Moderna: Grant/Research Support|Pfizer: Grant/Research Support|Vir Biotechnology: Grant/Research Support Emma Viscidi, PhD, MHS, Moderna: Stocks/Bonds (Public Company) John F. Dickerson, PhD, Janssesn: Grant/Research Support|Moderna: Grant/Research Support|Novartis: Grant/Research Support|Pfizer: Grant/Research Support Maureen O'Keeffe-Rosetti, MS, Hillevax: Grant/Research Support|Janssen: Grant/Research Support|Moderna: Grant/Research Support|Pfizer: Grant/Research Support Mark A. Schmidt, PhD, MPH, HilleVax: Grant/Research Support|Janssen: Grant/Research Support|Moderna: Grant/Research Support|Pfizer: Grant/Research Support|Vir Biotechnology: Grant/Research Support Laura H. Hendrix, MS, Moderna Therapeutics Ltd.: Stocks/Bonds (Private Company) Katherine B. Carlson, PhD, MPH, Moderna: Stocks/Bonds (Private Company)

P-5. Human Papillomavirus Vaccination Coverage Among Girls and Boys in the United States: A Birth Year Cohort Analysis of the National Immunization Survey-Teen, 2016–2022

Abstract Background Human papillomavirus (HPV) causes approximately 37,000 cancers in the United States annually. HPV vaccine, recommended by CDC at age 11 or 12 years, prevents more than 90% of HPV-attributable cancers. We aim to identify coverage gaps to guide targeted interventions. Methods We conducted a birth cohort analysis among adolescents born 1999-2009 using National Immunization Survey-Teen (NIS-Teen), a random-digit dialed telephone survey which also collects vaccination data from providers. We analyzed 131,553 records from 2016 to 2022 NIS-Teen data to determine: 1) trends in coverage with ≥ 1 HPV vaccine dose before age 13 years (on-time initiation), 2) cumulative coverage from 13 to 17 years (catch-up), 3) on-time HPV vaccination up to date status (all recommended doses before age 13 years), 4) missed vaccination opportunities (provider visits before age 13 years where HPV unvaccinated adolescents received other recommended vaccine but not HPV vaccine), and achievable coverage if HPV vaccination opportunities were not missed. Regression analysis provided the average percentage increase in coverage across birth cohorts. Kaplan-Meier method provided cumulative HPV vaccination coverage from age 13 to 17 years, stratified by birth cohorts. Results HPV vaccination coverage before 13 years increased from 27.0% among adolescents born in 1999 to 69.8% among those born in 2009. Coverage for girls increased from 37.4% to 73.4%; coverage for boys increased from 16.9% to 65.9%. Overall, coverage increased from 33.1% before age 13 years to 74.9% before age 18 years. HPV vaccination up to date status increase from 10.3% among adolescents in 1999 to 42.2% among those born in 2009. Among the 38,568 (29.3%) who had not received any HPV vaccination, 31,513 (82.5%) had ≥ 1 missed HPV vaccination opportunity. The potential achievable vaccination coverage if opportunities were not missed was 94.8%. Conclusion Coverage with on-time HPV vaccination and HPV up to date increased by birth cohort among adolescents born 1999–2009 but remains suboptimal. Low uptake increases risk for HPV cancers. Opportunities for HPV vaccination before age 13 years are being missed and can be reduced by effective provider recommendations for HPV vaccination and by administering all recommended vaccines during the same visit. Disclosures All Authors: No reported disclosures

Sustaining Vaccine Potency in Cold Chain Logistics: Numerical Analysis of Extended Cooling Duration in Glycerol-Infused n-Tetradecane Phase-Change Materials

Vaccination cold chains depend critically on maintaining temperatures within the 2–8 ∘C range, with phase-change materials (PCMs) like n-tetradecane offering substantial potential due to their high latent heat and optimal melting characteristics. Despite extensive research on PCM melting enhancement, strategies to extend melting duration and thermal stability remain underexplored. This pioneering numerical study investigates the impact of incorporating 5% glycerol additive in n-tetradecane, aiming to decelerate the melting rate and sustain the desired temperature range over prolonged periods. This study numerically assesses the effect of a 5% glycerol additive on n-tetradecane, revealing a substantial 20.6 h extension in safe temperature maintenance, from 123.3 h in pure n-tetradecane (T) to 143.9 h with the additive (T + G). Although T reaches full melting in 121.7 h, the air temperature inside the cold box breaches 8∘C only 1.6 h after; in contrast, T + G reaches this threshold 2.2 h before full melting, resulting in an effective extension of 20.6 h. Entropy analysis shows a delayed rise in T + G, indicating enhanced thermal stability, while temperature contours confirm T + G sustains cooling until day 6, a full day beyond T. These findings highlight glycerol’s potential to modulate thermal dynamics within PCM-based cold boxes, offering a cost-effective improvement in vaccine transport sustainability.

P-37. Factors Associated with Healthcare Professionals’ RSV Older Adult Vaccination Knowledge and Practices During the First Season of Vaccine Availability in the United States

Abstract Background In 2023, respiratory syncytial virus (RSV) vaccines were approved by the United States (US) Food and Drug Administration (FDA) for adults aged ≥60 years and recommended by the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices (ACIP) using shared clinical decision-making (SCDM). This study evaluated healthcare professional (HCP) characteristics associated with RSV vaccination knowledge and practices. Methods A cross-sectional online survey targeting approximately 600 HCPs was conducted in November 2023 to assess HCP knowledge, attitudes, and practices related to older adult RSV vaccination. Three logistic regression models used these survey data to explore HCP characteristics associated with RSV vaccination knowledge and practices (e.g., likelihood of knowing FDA indication and ACIP recommendation). The models included HCP type as a covariate a priori, with other covariates determined using backwards selection with a prespecified stay criterion (P < 0.1). Results The survey was completed by 603 HCPs (Table 1). HCPs had higher odds of being knowledgeable about the FDA indication and ACIP recommendation for older adult RSV vaccination if their workplace stocked RSV vaccine(s); odds were lower if HCPs were least familiar with RSV disease or had a higher percentage of non-White adult patients (Table 2). Odds of initiating RSV vaccination conversations with ≤5% of older adult patients were higher among HCPs who were less familiar with RSV disease, felt less confident in SCDM conversations, and perceived RSV protection to be less important than other respiratory infections (Table 3). Being less familiar with RSV disease was also associated with higher odds of not recommending/administering RSV vaccines to any older adults in the past 3 months (Table 4). Conclusion HCP familiarity with older adult RSV disease was associated with RSV vaccination knowledge and practices, highlighting the importance of continued RSV disease awareness efforts. Results can be used to tailor these efforts towards HCPs with potential vaccination knowledge and practice gaps to help ensure equitable RSV vaccination access across older adults. FUNDING: GSK (study identifier: VEO-000726) Disclosures Elizabeth M. La, PhD, GSK: employee|GSK: Stocks/Bonds (Private Company) David Singer, PharmD, MS, GSK: employee|GSK: Stocks/Bonds (Public Company) Eric Davenport, MStat, MEcon, GSK: study funding Andrea Harmelink, PhD, FNP, GSK: Stocks/Bonds (Public Company)

A Modular Bacteriophage T4 Nanoparticle Platform Enables Rapid Design of Dual COVID‐19‐Flu Mucosal Vaccines

A multivalent, rapidly deployable, mucosal vaccine platform is desperately needed to prevent acquisition and transmission of respiratory infections during epidemics and pandemics. No such approved platform currently exists and virtually all under investigation use infectious viruses that have safety concerns and are not amenable for multivalent engineering. Herein, a non‐infectious biomaterial platform is presented, the bacteriophage T4 nanoparticle endowed with unique features for modular engineering, which is exploited to design dual COVID‐Flu mucosal vaccines. By leveraging T4's natural affinity to nasal mucosa, in vivo CRISPR engineering, and in vitro SpyCatcher‐SpyTag conjugation, hundreds of antigen molecules are incorporated from SARS‐CoV‐2 and influenza viruses into one nanoparticle. These include spike and hemagglutinin trimers and M2e peptides decorating the capsid while encapsulating matrix or nucleocapsid proteins inside, thereby achieving unprecedented antigen density and diversity, a pinnacle nanoparticle design. Intranasal administration of this adjuvant‐free T4‐CoV‐Flu vaccine induces remarkable mucosal immunity against both respiratory pathogens, including high‐titer neutralizing antibodies and secretory IgA, lung‐resident CD4+/CD8+ T cells, diverse memory B cells, and complete protection against SARS‐CoV‐2 and influenza challenges. Coupled with its scalability in bacterial systems, thermostability, and adjuvant‐ and needle‐free delivery, T4 presents an extraordinary platform to design potent mucosal vaccines against pandemic threats.

Experiences, perceptions and ethical considerations of the malaria infection study in Thailand

BackgroundThailand has made significant progress in malaria control efforts in the past decade, with a decline in the number of reported cases. However, due to cross-border movements over the past 5 years, reported malaria cases in Thailand have risen. The Malaria Infection Study in Thailand (MIST) involves deliberate infection of healthy volunteers with Plasmodium vivax malaria parasites, and the assessment of the efficacy of potential vaccine and drug candidates in order to understand acquired protection against malaria parasites.MethodsThis paper drew from ethics and social science qualitative study called MIST-ETHICS embedded within the MIST studies. MIST-ETHICS aimed to describe and understand the experiences, perceptions and ethical considerations of the MIST studies. Data were obtained from semi-structured interviews and a focus group discussion. A total of 46 participants participated in MIST-ETHICS .ResultsThree major themes emerged: experiences and perceptions of MIST, reasons for joining MIST, and ethical considerations. We found that although compensation was a motivation for participation, this was secondary to it being beneficial to self (health checks; link to health networks; building merit) and others (medical research contribution; altruism). Participants expressed varied opinions regarding the requirement of a university degree as one of the inclusion criteria for MIST.ConclusionsOur study revealed widespread concerns about long-term health effects and safety. Ethical considerations, including obtaining valid informed consent and ensuring participant inclusivitiy, were deem essential. Despite some debate regarding eligibility criteria, most participants agreed that the informed consent process was robust, accompanied by a strong sense of responsibility to contribute to the greater good. We emphasize the importance of continuously gathering participants’ feedback for quality control, such as improving information materials to clarify the purpose of initial phases, their contributing to later phases, and the rationale behind each selection criterion.Trial registrationThis manuscript is part of the clinical trials registered under ClinicalTrials.gov IDs NCT04083508 (MIST1) registered on 5 Sep 2019 and NCT05071079 (MIST2) registered on 28 July 2021. However, the manuscript pertains to a qualitative study that does not require trial registration.

Epidemiology of invasive Haemophilus influenzae infections in Belgium: 2018-2022.

Haemophilus influenzae plays a major role in invasive bacterial infections. Resistant strains are emerging, prompting the WHO to include H. influenzae on its list of priority pathogens for research and development of new antibiotics. We aimed to describe the serotypes, demographics and susceptibility profiles of invasive strains collected in Belgium. Data on invasive strains referred to the Belgian National Reference Center for H. influenzae from 2018 to 2022 were analyzed retrospectively. A total of 608 invasive strains were included. The number of notifications per year ranged from 85 to 165, with a marked decrease between 2020 and 2021. The highest incidence rate was observed in Brussels (1.56 per 100,000 inhabitants over the five year 2018-2022). Sex and age distribution were in line with global trends, as was the predominance of the non-typeable H. influenzae (NTHI). Beta-lactam resistance varies between molecules: 18.9% for ampicillin, 5.6% for amoxicillin-clavulanate. Mutations in the ftsI gene associated with decreased susceptibility to beta-lactams increased from 11.5 to 17.7% over the period studied. The COVID-19 pandemic significantly influenced the epidemiology of invasive H. influenzae infections in Belgium. Demographic analysis identified a significant male predominance among infants, with a male-to-female ratio of 2.57 in patients under one year of age, a high figure not previously reported in the literature. The continued predominance of NTHI underscores the efficacy of Hib vaccination, although the emergence of Hib in patients younger than five years in 2022 suggests an alarming serotype dynamic. The detection of meropenem resistance also highlights the growing threat of antimicrobial resistance, while the increase in ftsI gene mutations raises concerns about the efficacy of first-line treatment. This study provides a comprehensive overview of the epidemiology of invasive H. influenzae infections in Belgium, focusing on demographic changes, serotype predominance and antimicrobial resistance trends. Vigilant surveillance and research are essential to address emerging challenges and guide future interventions, including potential vaccine development.

Genetic diversity of Plasmodium falciparum reticulocyte binding protein homologue-5, which is a potential malaria vaccine candidate: baseline data from areas of varying malaria endemicity in Mainland Tanzania

BackgroundThe limited efficacy of the two recently approved malaria vaccines, RTS,S/AS01 and R21/Matrix- M™, highlights the need for alternative vaccine candidate genes. Plasmodium falciparum Reticulocyte Binding Protein Homologue 5 (Pfrh5) is a promising malaria vaccine candidate, given its limited polymorphism, its essential role in parasite survival, a lack of immune selection pressure and higher efficacy against multiple parasites strains. This study evaluated the genetic diversity of Pfrh5 gene among parasites from regions with varying malaria transmission intensities in Mainland Tanzania, to generate baseline data for this potential malaria vaccine candidate.MethodsThis study utilized secondary data of 697 whole-genome sequences which were generated by the MalariaGEN Community Network. The samples which were sequenced to generated the data were collected between 2010 and 2015 from five districts within five regions of Mainland Tanzania, with varying endemicities (Morogoro-urban district in Morogoro region, Muheza in Tanga, Kigoma-Ujiji in Kigoma, Muleba in Kagera, and Nachingwea district in Lindi region). Wright's fixation index (FST), Wright’s inbreeding coefficient (Fws), Principal component analysis (PCA), nucleotide diversity (π), haplotype network, haplotype diversity (Hd), Tajima's D, and Linkage disequilibrium (LD) were used to assess the diversity of the gene.ResultsOf the sequences used in this study, 84.5% (n = 589/697) passed quality control and 313 (53.1%) were monoclonal (contained infections from a single strain of P. falciparum) and were used for haplotype diversity and haplotype network analysis. High within-host diversity (Fws < 0.95) was reported in Kigoma-Ujiji (60.7%), Morogoro-urban (53.1%), and Nachingwea (50.8%), while Muleba (53.9%) and Muheza (61.6%) had low within-host diversity (Fws ≥ 0.95). PCA did not show any population structure and the mean FST value was 0.015. Low nucleotide diversity values were observed across the study sites (mean π = 0.00056). A total of 27 haplotypes were observed among the 313 monoclonal samples and under-fives exhibited higher haplotype counts. The Pf3D7 was detected as Hap_1, which occurred in 16/313 (5.1%) monoclonal sequences. Negative Tajima's D values were observed among the parasite populations in all the study sites.ConclusionLow levels of polymorphism in the pfrh5 gene were observed based on low nucleotide and haplotype diversity, a lack of population structure and negative Tajima’s D values. This study provides essential data on the diversity of the Pfrh5 gene indicating that it can be considered in the development of the next generation malaria vaccines. Robust and intensive studies of this and other candidate genes are crucial to support the prioritization of the Pfrh5 gene for potential inclusion in a broadly cross-protective malaria vaccine.

Optimization of Enterovirus-like Particle Production and Purification Using Design of Experiments

Hand, foot, and mouth disease (HFMD) represents an emerging health concern whose main causative agents are Coxsackievirus A6 (CVA6) and enterovirus A71 (EV71). The lack of a CVA6 vaccine and the rise of new HFMD-causing strains due to the containment of established HFMD-causing viruses necessitates the search for alternative vaccine technologies, including virus-like particle (VLP) vaccine candidates. While studies have demonstrated that production of enterovirus-like particles in various organisms can be achieved by expression of the viral P1 structural proteins and the 3CD protease, optimization based on the interplay between the three most commonly altered infection parameters (multiplicity of infection (MOI), viable cell density at the time of infection (VCD), and the infection period) is often not investigated. To address this challenge, we have performed Design of Experiments (DoE) to optimize the production of CVA6 and EV71 VLPs. Our results indicate that CVA6 VLP production peaks at high MOI, high VCD, and long infection periods. Our subsequent downstream purification processes yielded 38 mg and 158 mg of purified CVA6 and EV71 VLPs from 1 L crude harvest, respectively. This translates into thousands of potential vaccine doses and highlights the economic potential of enterovirus-like particles for vaccine purposes.

Computational Design of a Multi-Epitope Vaccine against Prevotella copri: Molecular Dynamics and Immunoinformatics Study

Prevotella copri is a prominent constituent of the human gastrointestinal microbiome, and its fluctuating abundance has been linked with positive and negative influences on diseases such as Parkinson’s disease and rheumatoid arthritis. Prevotella copri demonstrates flexibility against drugs. There is presently no vaccine approved by the FDA against prevotella copri,and treatment options are restricted. Hence, this research work was designed to create an in silico-based vaccine for prevotella copri.The protein sequences of two distinct strains ofprevotella copriwere retrieved from NCBI. The T-cell and B-cell epitopes were obtained and then analyzed for antigenicity, allergenicity, docking and simulation. The peptide comprises linear B-cell and T-cell epitopes from proteins identified as potential novel vaccine candidates. The molecular dynamics (MD) simulations and protein-protein docking results revealed that the vaccine exhibits strong and Sustained interaction with Toll-like receptor 4 (TLR4). The constructed sequence was integrated into the pET-30a (+) biological vehicle (vector) for subsequent analysis expression in E. coli through the SnapGene server. The constructed multi-epitopic vaccine candidate was assessed for its structural, physicochemical and immunological properties. The results demonstrated solubility, stability, antigenicity and nonallergenicity and showed a strong affinity for its target receptors. The in silico study represents a significant step forward in designing a vaccine that could effectively eliminate Prevotella copri globally.

SENSITIVITY ANALYSIS AND NUMERICAL MODELING OF INFLUENZA PROPAGATION AND INTERVENTION STRATEGIES UNDER THE FRACTAL-FRACTIONAL OPERATOR

This paper introduces a novel nonlinear fractal fractional model to comprehensively analyze influenza epidemics. By integrating fractional calculus and considering nonlinear interactions among individuals, the model utilizes the Fractal-Fractional (FF) operator. This operator, combining fractal and fractional calculus, establishes a unique framework for investigating influenza virus propagation dynamics and potential vaccination strategies. Amid growing concerns over influenza outbreaks, fractional derivatives are employed to address intricate challenges. The proposed model sheds light on virus spread dynamics and countermeasures. The integration of the FF operator enriches analysis, while the application of the fixed point theory of Schauder and Banach demonstrates solution existence and uniqueness. Model validation employs numerical simulations with MATLAB12̂ and the Adams–Bashforth method, confirming its ability to capture influenza propagation dynamics accurately. Ulam–Hyers stability techniques ensure the model’s reliability. Beyond its scientific contributions, the model underscores the significance of studying influenza epidemics via mathematical modeling in understanding disease dynamics and guiding effective intervention strategies. Through a synergy of mathematical innovation and epidemiological insights, this study establishes a robust foundation for more effective strategies against influenza epidemics.

A VCG-Based Multiepitope Chlamydia Vaccine Incorporating the Cholera Toxin A1 Subunit (MECA) Confers Protective Immunity Against Transcervical Challenge

Background/Objectives: We generated a novel recombinant Vibrio cholerae ghost (rVCG)-based subunit vaccine incorporating the A1 subunit of cholera toxin (CTA1) and a multiepitope Chlamydia trachomatis (CT) antigen (MECA) derived from five chlamydial outer membrane proteins (rVCG-MECA). The ability of this vaccine to protect against a CT transcervical challenge was evaluated. Methods: Female C57BL/6J mice were immunized thrice at two-week intervals with rVCG-MECA or rVCG-gD2 (antigen control) via the intramuscular (IM) or intranasal (IN) route. PBS-immunized mice or mice immunized with live CT served as negative and positive controls, respectively. Results: Vaccine delivery stimulated robust humoral and cell-mediated immune effectors, characterized by local mucosal and systemic CT-specific IgG, IgG2c, and IgA antibody and IFN-γ (Th1 cytokine) responses. The elicited mucosal and systemic IgG2c and IgA antibody responses persisted for 16 weeks post-immunization. Immunization with rVCG-MECA afforded protection comparable to that provided by IN immunization with live CT EBs without any side effects, irrespective of route of vaccine delivery. Conclusions: The results underline the potential of a multiepitope vaccine as a promising resource for protecting against CT genital infection and the potential of CTA1 on the VCG platform as a mucosal and systemic adjuvant for developing CT vaccines.