Design and characterization of protective pan-ebolavirus and pan-filovirus bispecific antibodies.

Monoclonal antibodies (mAbs) are an important class of antiviral therapeutics. MAbs are highly selective, well tolerated, and have long in vivo half-life as well as the capacity to induce immune-mediated virus clearance. Their activities can be further enhanced by integration of their variable fragments (Fvs) into bispecific antibodies (bsAbs), affording simultaneous targeting of multiple epitopes to improve potency and breadth and/or to mitigate against viral escape by a single mutation. Here, we explore a bsAb strategy for generation of pan-ebolavirus and pan-filovirus immunotherapeutics. Filoviruses, including Ebola virus (EBOV), Sudan virus (SUDV), and Marburg virus (MARV), cause severe hemorrhagic fever. Although there are two FDA-approved mAb therapies for EBOV infection, these do not extend to other filoviruses. Here, we combine Fvs from broad ebolavirus mAbs to generate novel pan-ebolavirus bsAbs that are potently neutralizing, confer protection in mice, and are resistant to viral escape. Moreover, we combine Fvs from pan-ebolavirus mAbs with those of protective MARV mAbs to generate pan-filovirus protective bsAbs. These results provide guidelines for broad antiviral bsAb design and generate new immunotherapeutic candidates.

Assessment of the integrated disease surveillance and response system implementation in health zones at risk for viral hemorrhagic fever outbreaks in North Kivu, Democratic Republic of the Congo, following a major Ebola outbreak, 2021.

BACKGROUND: The Democratic Republic of the Congo (DRC) experienced its largest Ebola Virus Disease Outbreak in 2018-2020. As a result of the outbreak, significant funding and international support were provided to Eastern DRC to improve disease surveillance. The Integrated Disease Surveillance and Response (IDSR) strategy has been used in the DRC as a framework to strengthen public health surveillance, and full implementation could be critical as the DRC continues to face threats of various epidemic-prone diseases. In 2021, the DRC initiated an IDSR assessment in North Kivu province to assess the capabilities of the public health system to detect and respond to new public health threats. METHODS: The study utilized a mixed-methods design consisting of quantitative and qualitative methods. Quantitative assessment of the performance in IDSR core functions was conducted at multiple levels of the tiered health system through a standardized questionnaire and analysis of health data. Qualitative data were also collected through observations, focus groups and open-ended questions. Data were collected at the North Kivu provincial public health office, five health zones, 66 healthcare facilities, and from community health workers in 15 health areas. RESULTS: Thirty-six percent of health facilities had no case definition documents and 53% had no blank case reporting forms, limiting identification and reporting. Data completeness and timeliness among health facilities were 53% and 75% overall but varied widely by health zone. While these indicators seemingly improved at the health zone level at 100% and 97% respectively, the health facility data feeding into the reporting structure were inconsistent. The use of electronic Integrated Disease Surveillance and Response is not widely implemented. Rapid response teams were generally available, but functionality was low with lack of guidance documents and long response times. CONCLUSION: Support is needed at the lower levels of the public health system and to address specific zones with low performance. Limitations in materials, resources for communication and transportation, and workforce training continue to be challenges. This assessment highlights the need to move from outbreak-focused support and funding to building systems that can improve the long-term functionality of the routine disease surveillance system.

Methodological issues of retrospective surveys for measuring mortality of highly clustered diseases: case study of the 2014-16 Ebola outbreak in Bo District, Sierra Leone.

BACKGROUND: There is a lack of empirical data on design effects (DEFF) for mortality rate for highly clustered data such as with Ebola virus disease (EVD), along with a lack of documentation of methodological limitations and operational utility of mortality estimated from cluster-sampled studies when the DEFF is high. OBJECTIVES: The objectives of this paper are to report EVD mortality rate and DEFF estimates, and discuss the methodological limitations of cluster surveys when data are highly clustered such as during an EVD outbreak. METHODS: We analysed the outputs of two independent population-based surveys conducted at the end of the 2014-2016 EVD outbreak in Bo District, Sierra Leone, in urban and rural areas. In each area, 35 clusters of 14 households were selected with probability proportional to population size. We collected information on morbidity, mortality and changes in household composition during the recall period (May 2014 to April 2015). Rates were calculated for all-cause, all-age, under-5 and EVD-specific mortality, respectively, by areas and overall. Crude and adjusted mortality rates were estimated using Poisson regression, accounting for the surveys sample weights and the clustered design. RESULTS: Overall 980 households and 6,522 individuals participated in both surveys. A total of 64 deaths were reported, of which 20 were attributed to EVD. The crude and EVD-specific mortality rates were 0.35/10,000 person-days (95%CI: 0.23-0.52) and 0.12/10,000 person-days (95%CI: 0.05-0.32), respectively. The DEFF for EVD mortality was 5.53, and for non-EVD mortality, it was 1.53. DEFF for EVD-specific mortality was 6.18 in the rural area and 0.58 in the urban area. DEFF for non-EVD-specific mortality was 1.87 in the rural area and 0.44 in the urban area. CONCLUSION: Our findings demonstrate a high degree of clustering; this contributed to imprecise mortality estimates, which have limited utility when assessing the impact of disease. We provide DEFF estimates that can inform future cluster surveys and discuss design improvements to mitigate the limitations of surveys for highly clustered data.

Main findings: For humanitarian organizations it is imperative to document the methodological limitations of cluster surveys and discuss the utility.Added knowledge: This paper adds new knowledge on cluster surveys for highly clustered data such us in Ebola virus disease.Global health impact of policy and action: We provided empirical estimates and discuss design improvements to inform future study.

Ebola-specific therapeutic antibodies from lab to clinic: The example of ZMapp.

In the 1990s, monoclonal antibodies (mAbs) progressed from scientific tools to advanced therapeutics, particularly for the treatment of cancers and autoimmune and inflammatory disorders. In the arena of infectious disease, the inauguration of mAbs as a post-exposure treatment in humans against Ebola virus (EBOV) occurred in response to the 2013-2016 West Africa outbreak. This review recounts the history of a candidate mAb treatment, ZMapp, beginning with its emergency use in the 2013-2016 outbreak and advancing to randomized controlled trials into the 2018-2020 African outbreak. We end with a brief discussion of the hurdles and promise toward mAb therapeutic use against infectious disease.

Computational and stability analysis of Ebola virus epidemic model with piecewise hybrid fractional operator.

In this manuscript, we developed a nonlinear fractional order Ebola virus with a novel piecewise hybrid technique to observe the dynamical transmission having eight compartments. The existence and uniqueness of a solution of piecewise derivative is treated for a system with Arzel'a-Ascoli and Schauder conditions. We investigate the effects of classical and modified fractional calculus operators, specifically the classical Caputo piecewise operator, on the behavior of the model. A model shows that a completely continuous operator is uniformly continuous, and bounded according to the equilibrium points. The reproductive number R0 is derived for the biological feasibility of the model with sensitivity analysis with different parameters impact on the model. Sensitivity analysis is an essential tool for comprehending how various model parameters affect the spread of illness. Through a methodical manipulation of important parameters and an assessment of their impact on Ro, we are able to learn more about the resiliency and susceptibility of the model. Local stability is established with next Matignon method and global stability is conducted with the Lyapunov function for a feasible solution of the proposed model. In the end, a numerical solution is derived with Newton's polynomial technique for a piecewise Caputo operator through simulations of the compartments at various fractional orders by using real data. Our findings highlight the importance of fractional operators in enhancing the accuracy of the model in capturing the intricate dynamics of the disease. This research contributes to a deeper understanding of Ebola virus dynamics and provides valuable insights for improving disease modeling and public health strategies.

Peak transgene expression after intramuscular immunization of mice with adenovirus 26-based vector vaccines correlates with transgene-specific adaptive immune responses.

Non-replicating adenovirus-based vectors have been broadly used for the development of prophylactic vaccines in humans and are licensed for COVID-19 and Ebola virus disease prevention. Adenovirus-based vectored vaccines encode for one or more disease specific transgenes with the aim to induce protective immunity against the target disease. The magnitude and duration of transgene expression of adenovirus 5- based vectors (human type C) in the host are key factors influencing antigen presentation and adaptive immune responses. Here we characterize the magnitude, duration, and organ biodistribution of transgene expression after single intramuscular administration of adenovirus 26-based vector vaccines in mice and evaluate the differences with adenovirus 5-based vector vaccine to understand if this is universally applicable across serotypes. We demonstrate a correlation between peak transgene expression early after adenovirus 26-based vaccination and transgene-specific cellular and humoral immune responses for a model antigen and SARS-CoV-2 spike protein, independent of innate immune activation. Notably, the memory immune response was similar in mice immunized with adenovirus 26-based vaccine and adenovirus 5-based vaccine, despite the latter inducing a higher peak of transgene expression early after immunization and a longer duration of transgene expression. Together these results provide further insights into the mode of action of adenovirus 26-based vector vaccines.

Perceptions, attitudes, and willingness of healthcare and frontline workers to participate in an Ebola vaccine trial in Uganda.

BACKGROUND: Understanding the knowledge, perception and attitudes towards Ebola vaccines is an important factor in ensuring future use of these vaccines. A qualitative methods study embedded in an Ebola vaccine immunogenicity and safety trial (NCT04028349) was conducted to explore the knowledge and perceptions of healthcare (HCWs) and frontline workers (FLWs), about Ebola vaccines and their willingness to participate or recommend participation in Uganda. METHOD: We carried out focus group discussions and semi-structured interviews before and after vaccination, with 70 HCWs and FLWs who consented to participate in the trial, and in the qualitative component, from August to September 2019. Data were analysed using thematic content analysis. RESULTS: Respondents showed good knowledge about Ebola and the vaccines in general, and had wide access to information through several channels, including the study team. On prevention, particular attention was given to effective communication within health facilities. Misconceptions were mainly around route of transmission, animal origin and types of vaccines. Previous fears were based on rumours circulating in the community, mainly about the presence of the virus in the vaccine, side effects and intention to harm (e.g. by "the whites"), ultimately insisting on transparency, trust and involvement of local leaders. Acceptability of participation was motivated by the need to protect self and others, and the willingness to advance research. Majority were willing to recommend participation to their community. CONCLUSIONS: Overall, information sharing leads to a better understanding and acceptance of vaccine trials and a positive vaccination experience can be a deciding factor in the acceptance of others. Particular attention should be paid to involving the community in addressing misconceptions and fears, while ensuring that participants have access to vaccination sites in terms of transport, and that they are properly accommodated at the study site including staying for a reasonable period of time.

The Role of Ebola Virus VP24 Nuclear Trafficking Signals in Infectious Particle Production.

Ebola virus (EBOV) protein VP24 carries out at least two critical functions. It promotes condensation of viral nucleocapsids, which is crucial for infectious virus production, and it suppresses interferon (IFN) signaling, which requires interaction with the NPI-1 subfamily of importin-α (IMPA) nuclear transport proteins. Interestingly, over-expressed IMPA leads to VP24 nuclear accumulation and a carboxy-terminus nuclear export signal (NES) has been reported, suggesting that VP24 may undergo nuclear trafficking. For the first time, we demonstrate that NPI-1 IMPA overexpression leads to the nuclear accumulation of VP24 during EBOV infection. To assess the functional impact of nuclear trafficking, we generated tetracistronic minigenomes encoding VP24 nuclear import and/or export signal mutants. The minigenomes, which also encode Renilla luciferase and viral proteins VP40 and GP, were used to generate transcription and replication competent virus-like particles (trVLPs) that can be used to assess EBOV RNA synthesis, gene expression, entry and viral particle production. With this system, we confirmed that NES or IMPA binding site mutations altered VP24 nuclear localization, demonstrating functional trafficking signals. While these mutations minimally affected transcription and replication, the trVLPs exhibited impaired infectivity and formation of shortened nucleocapsids for the IMPA binding mutant. For the NES mutants, infectivity was reduced approximately 1000-fold. The NES mutant could still suppress IFN signaling but failed to promote nucleocapsid formation. To determine whether VP24 nuclear export is required for infectivity, the residues surrounding the wildtype NES were mutated to alanine or the VP24 NES was replaced with the Protein Kinase A Inhibitor NES. While nuclear export remained intact for these mutants, infectivity was severely impaired. These data demonstrate that VP24 undergoes nuclear trafficking and illuminates a separate and critical role for the NES and surrounding sequences in infectivity and nucleocapsid assembly.

Safety and Immunogenicity of Accelerated Heterologous Two-dose Ebola Vaccine Regimens in Adults With and Without HIV in Africa.

BACKGROUND: Shorter prophylactic vaccine schedules may offer more rapid protection against Ebola in resource-limited settings. METHODS: This randomized, observer-blind, placebo-controlled, phase 2 trial conducted in five sub-Saharan African countries included people without HIV (PWOH, n = 249) and people living with HIV (PLWH, n = 250). Adult participants received one of two accelerated Ebola vaccine regimens (MVA-BN-Filo, Ad26.ZEBOV administered 14 days apart [n = 79] or Ad26.ZEBOV, MVA-BN-Filo administered 28 days apart [n = 322]) or saline/placebo (n = 98). The primary endpoints were safety (adverse events [AEs]) and immunogenicity (Ebola virus [EBOV] glycoprotein-specific binding antibody responses). Binding antibody responders were defined as participants with a > 2.5-fold increase from baseline or the lower limit of quantification if negative at baseline. RESULTS: The mean age was 33.4 years, 52% of participants were female, and among PLWH, the median (interquartile range) CD4+ cell count was 560.0 (418.0-752.0) cells/µL. AEs were generally mild/moderate with no vaccine-related serious AEs or remarkable safety profile differences by HIV status. At 21 days post-dose 2, EBOV glycoprotein-specific binding antibody response rates in vaccine recipients were 99% for the 14-day regimen (geometric mean concentrations [GMCs]: 5168 enzyme-linked immunosorbent assay units (EU)/mL in PWOH; 2509 EU/mL in PLWH), and 98% for the 28-day regimen (GMCs: 6037 EU/mL in PWOH; 2939 EU/mL in PLWH). At 12 months post-dose 2, GMCs in PWOH and PLWH were 635 and 514 EU/mL, respectively, for the 14-day regimen and 331 and 360 EU/mL, respectively, for the 28-day regimen. CONCLUSIONS: Accelerated 14- and 28-day Ebola vaccine regimens were safe and immunogenic in PWOH and PLWH in Africa. TRIAL REGISTRATION: NCT02598388.

Readiness To Manage Ebola Virus Disease Among Emergency Healthcare Workers in Uganda: A Nationwide Multicenter Survey.

Background Emerging infectious diseases like the Ebola Virus Disease (EVD) pose significant global public health threats. Uganda has experienced multiple EVD outbreaks, the latest occurring in 2022. Frontline healthcare workers (HCWs) are at increased risk, yet there isn't sufficient evidence of existing knowledge of EVD of these health workers. We aimed to assess the readiness of Uganda's emergency healthcare workers to manage Ebola virus disease (EVD) and identify their training needs to inform targeted capacity-building interventions for future outbreaks. Methods This multicentre nationwide cross-sectional study was conducted from July to August 2023 among 691 HCWs providing emergency care in 14 secondary and tertiary hospitals across Uganda. Participants were consecutively recruited using the probability-proportional-to-size sampling technique, and data was collected using a self-reported questionnaire. Factors associated with EVD knowledge were identified through a mixed-effect linear model. Results Data from 691 eligible HCWs with a median age of 32 (IQR: 28-38) was analyzed (response rate: 92%). Only one-third (34.4%, n = 238) had received EVD training in the past year. The median EVD knowledge score was 77.4% (IQR: 71.2% - 83.4%). EVD knowledge was associated with longer professional experience in years (ß: 0.21, 95% CI: 0.03 to 0.39, p = 0.024) and higher level of education: diploma (ß: 3.37, 95% CI: 1.49 to 5.25, p < 0.001), undergraduate degree (ß: 6.45, 95% CI: 4.11 to 8.79) and postgraduate degree (ß: 7.13, 95% CI: 4.01 to 10.25, p < 0.001). Being a doctor (ß: 2.55, 95% CI: 0.35 to 4.74, p = 0.023), providing care in the obstetrics/gynecology department (ß: -1.90, 95% CI: -3.47 to - 0.32, p = 0.018), previous EVD training (ß: 2.27, 95% CI: 0.96 to 3.59, p = 0.001) and accessing EVD information through social media (ß: 2.52, 95% CI: 1.17 to 3.88, p < 0.001) were also significantly associated with EVD knowledge. Conclusion Our study reveals that Ugandan HCWs' EVD response readiness varies by individual factors and information sources. We recommend targeted training and suggest future research on educational innovations and social media's potential to fill knowledge gaps.

Development of a non-infectious control for viral hemorrhagic fever PCR assays.

Assay validation is an essential component of disease surveillance testing, but can be problematic in settings where access to positive control material is limited and a safety risk for handlers. Here we describe a single non-infectious synthetic control that can help develop and validate the PCR based detection of the viral causes of Crimean-Congo hemorrhagic fever, Ebola virus disease, Lassa fever, Marburg virus disease and Rift Valley fever. We designed non-infectious synthetic DNA oligonucleotide sequences incorporating primer binding sites suitable for five assays, and a T7 promotor site which was used to transcribe the sequence. Transcribed RNA was used as template in a dilution series, extracted and amplified with RT-PCR and RT-qPCR to demonstrate successful recovery and determine limits of detection in a range of laboratory settings. Our results show this approach is adaptable to any diagnostic assay requiring validation of nucleic acid extraction and/or amplification, particularly where sourcing reliable, safe material for positive controls is infeasible.

Mapping of susceptibility loci for Ebola virus pathogenesis in mice.

Ebola virus (EBOV), a major global health concern, causes severe, often fatal EBOV disease (EVD) in humans. Host genetic variation plays a critical role, yet the identity of host susceptibility loci in mammals remains unknown. Using genetic reference populations, we generate an F2 mapping cohort to identify host susceptibility loci that regulate EVD. While disease-resistant mice display minimal pathogenesis, susceptible mice display severe liver pathology consistent with EVD-like disease and transcriptional signatures associated with inflammatory and liver metabolic processes. A significant quantitative trait locus (QTL) for virus RNA load in blood is identified in chromosome (chr)8, and a severe clinical disease and mortality QTL is mapped to chr7, which includes the Trim5 locus. Using knockout mice, we validate the Trim5 locus as one potential driver of liver failure and mortality after infection. The identification of susceptibility loci provides insight into molecular genetic mechanisms regulating EVD progression and severity, potentially informing therapeutics and vaccination strategies.

Engaging the public in decisions about emergency vaccine deployment strategies: Lessons from scenario-based discussions in Sierra Leone.

ABSTRACTThe COVID-19 pandemic has amplified discussions on emergency vaccine deployment strategies, with current perspectives often neglecting extensive community involvement in ethical, logistical and political aspects. Existing social science literature predominantly delves into factors influencing trust, overlooking the untapped potential for community engagement.Our study examines community preparedness in Sierra Leone's Kambia District, exploring diverse viewpoints on vaccine deployment strategies, emphasising Ebola and COVID-19 vaccinations. Utilising extensive ethnographic research from the Ebola vaccine trials (EBOVAC Salone) conducted in Kambia District from 2015 to 2021, including participant observation and tailored focus group discussions, we investigated various deployment scenarios with community leaders and citizens.Our findings underscore the multifaceted contributions of social science research with communities in shaping emergency vaccination strategies. These contributions span logistical insights, aligning campaigns with local livelihoods and social structures, and grounded ethical concerns assessing social justice outcomes across epidemic scenarios. This study emphasises the imperative of integrating discussions on vaccine confidence and deployment. It highlights communities' proficiency in epidemiological reasoning and their ability to bring this in conversation with salient socio-cultural, economic and religious dimensions. We therefore promote the cultivation of public dialogue, collaborative creation of impactful vaccination initiatives alongside relevant communities in recognition of their invaluable perspectives .

Single-cell image-based genetic screens systematically identify regulators of Ebola virus subcellular infection dynamics.

Ebola virus (EBOV) is a high-consequence filovirus that gives rise to frequent epidemics with high case fatality rates and few therapeutic options. Here, we applied image-based screening of a genome-wide CRISPR library to systematically identify host cell regulators of Ebola virus infection in 39,085,093 million single cells. Measuring viral RNA and protein levels together with their localization in cells identified over 998 related host factors and provided detailed information about the role of each gene across the virus replication cycle. We trained a deep learning model on single-cell images to associate each host factor with predicted replication steps, and confirmed the predicted relationship for select host factors. Among the findings, we showed that the mitochondrial complex III subunit UQCRB is a post-entry regulator of Ebola virus RNA replication, and demonstrated that UQCRB inhibition with a small molecule reduced overall Ebola virus infection with an IC50 of 5 µM. Using a random forest model, we also identified perturbations that reduced infection by disrupting the equilibrium between viral RNA and protein. One such protein, STRAP, is a spliceosome-associated factor that was found to be closely associated with VP35, a viral protein required for RNA processing. Loss of STRAP expression resulted in a reduction in full-length viral genome production and subsequent production of non-infectious virus particles. Overall, the data produced in this genome-wide high-content single-cell screen and secondary screens in additional cell lines and related filoviruses (MARV and SUDV) revealed new insights about the role of host factors in virus replication and potential new targets for therapeutic intervention.

Helminth exposure and immune response to the two-dose heterologous Ad26.ZEBOV, MVA-BN-Filo Ebola vaccine regimen.

BACKGROUND: The exposure to parasites may influence the immune response to vaccines in endemic African countries. In this study, we aimed to assess the association between helminth exposure to the most prevalent parasitic infections, schistosomiasis, soil transmitted helminths infection and filariasis, and the Ebola virus glycoprotein (EBOV GP) antibody concentration in response to vaccination with the Ad26.ZEBOV, MVA-BN-Filo vaccine regimen in African and European participants using samples obtained from three international clinical trials. METHODS/PRINCIPAL FINDINGS: We conducted a study in a subset of participants in the EBL2001, EBL2002 and EBL3001 clinical trials that evaluated the Ad26.ZEBOV, MVA-BN-Filo vaccine regimen against EVD in children, adolescents and adults from the United Kingdom, France, Burkina Faso, Cote d'Ivoire, Kenya, Uganda and Sierra Leone. Immune markers of helminth exposure at baseline were evaluated by ELISA with three commercial kits which detect IgG antibodies against schistosome, filarial and Strongyloides antigens. Luminex technology was used to measure inflammatory and activation markers, and Th1/Th2/Th17 cytokines at baseline. The association between binding IgG antibodies specific to EBOV GP (measured on day 21 post-dose 2 and on Day 365 after the first dose respectively), and helminth exposure at baseline was evaluated using a multivariable linear regression model adjusted for age and study group. Seventy-eight (21.3%) of the 367 participants included in the study had at least one helminth positive ELISA test at baseline, with differences of prevalence between studies and an increased prevalence with age. The most frequently detected antibodies were those to Schistosoma mansoni (10.9%), followed by Acanthocheilonema viteae (9%) and then Strongyloides ratti (7.9%). Among the 41 immunological analytes tested, five were significantly (p < .003) lower in participants with at least one positive helminth ELISA test result: CCL2/MCP1, FGFbasic, IL-7, IL-13 and CCL11/Eotaxin compared to participants with negative helminth ELISA tests. No significant association was found with EBOV-GP specific antibody concentration at 21 days post-dose 2, or at 365 days post-dose 1, adjusted for age group, study, and the presence of any helminth antibodies at baseline. CONCLUSIONS/SIGNIFICANCE: No clear association was found between immune markers of helminth exposure as measured by ELISA and post-vaccination response to the Ebola Ad26.ZEBOV/ MVA-BN-Filo vaccine regimen. TRIAL REGISTRATION: NCT02416453, NCT02564523, NCT02509494. ClinicalTrials.gov.

Public health surveillance through community health workers: a scoping review of evidence from 25 low-income and middle-income countries.

BACKGROUND: The last 3 years have witnessed global health challenges, ranging from the pandemics of COVID-19 and mpox (monkeypox) to the Ebola epidemic in Uganda. Public health surveillance is critical for preventing these outbreaks, yet surveillance systems in resource-constrained contexts struggle to provide timely disease reporting. Although community health workers (CHWs) support health systems in low-income and middle-income countries (LMICs), very little has been written about their role in supporting public health surveillance. This review identified the roles, impacts and challenges CHWs face in public health surveillance in 25 LMICs. METHODS: We conducted a scoping review guided by Arksey and O'Malley's framework. We exported 1,156 peer-reviewed records from Embase, Global Health and PubMed databases. After multiple screenings, 29 articles were included in the final review. RESULTS: CHWs significantly contribute to public health surveillance in LMICs including through contact tracing and patient visitation to control major infectious diseases such as HIV/AIDS, malaria, tuberculosis, Ebola, neglected tropical diseases and COVID-19. Their public health surveillance roles typically fall into four main categories including community engagement; data gathering; screening, testing and treating; and health education and promotion. The use of CHWs in public health surveillance in LMICs has been impactful and often involves incorporation of various technologies leading to improved epidemic control and disease reporting. Nonetheless, use of CHWs can come with four main challenges including lack of education and training, lack of financial and other resources, logistical and infrastructural challenges as well as community engagement challenges. CONCLUSION: CHWs are important stakeholders in surveillance because they are closer to communities than other healthcare workers. Further integration and training of CHWs in public health surveillance would improve public health surveillance because CHWs can provide health data on 'hard-to-reach' populations. CHWs' work in public health surveillance would also be greatly enhanced by infrastructural investments.

Use of Ebola Vaccines - Worldwide, 2021-2023.

Ebola virus disease (Ebola) is a rare but severe illness in humans, with an average case fatality rate of approximately 50%. Two licensed vaccines are currently available against Orthoebolavirus zairense, the virus that causes Ebola: the 1-dose rVSVΔG-ZEBOV-GP (ERVEBO [Merck]) and the 2-dose regimen of Ad26.ZEBOV and MVA-BN-Filo (Zabdeno/Mvabea [Johnson & Johnson]). The Strategic Advisory Group of Experts on Immunization recommends the use of 1-dose ERVEBO during Ebola outbreaks, and in 2021, a global stockpile of ERVEBO was established to ensure equitable, timely, and targeted access to vaccine doses for future Ebola outbreaks. This report describes the use of Ebola vaccines and the role of the stockpile developed and managed by the International Coordinating Group (ICG) on Vaccine Provision during 2021-2023. A total of 145,690 doses have been shipped from the ICG stockpile since 2021. However, because outbreaks since 2021 have been limited and rapidly contained, most doses (139,120; 95%) shipped from the ICG stockpile have been repurposed for preventive vaccination of high-risk groups, compared with 6,570 (5%) used for outbreak response. Repurposing doses for preventive vaccination could be prioritized in the absence of Ebola outbreaks to prevent transmission and maximize the cost-efficiency and benefits of the stockpile.

Computational and experimental identification of keystone interactions in Ebola virus matrix protein VP40 dimer formation.

The Ebola virus (EBOV) is a lipid-enveloped virus with a negative sense RNA genome that can cause severe and often fatal viral hemorrhagic fever. The assembly and budding of EBOV is regulated by the matrix protein, VP40, which is a peripheral protein that associates with anionic lipids at the inner leaflet of the plasma membrane. VP40 is sufficient to form virus-like particles (VLPs) from cells, which are nearly indistinguishable from authentic virions. Due to the restrictions of studying EBOV in BSL-4 facilities, VP40 has served as a surrogate in cellular studies to examine the EBOV assembly and budding process from the host cell plasma membrane. VP40 is a dimer where inhibition of dimer formation halts budding and formation of new VLPs as well as VP40 localization to the plasma membrane inner leaflet. To better understand VP40 dimer stability and critical amino acids to VP40 dimer formation, we integrated computational approaches with experimental validation. Site saturation/alanine scanning calculation, combined with molecular mechanics-based generalized Born with Poisson-Boltzmann surface area (MM-GB/PBSA) method and molecular dynamics simulations were used to predict the energetic contribution of amino acids to VP40 dimer stability and the hydrogen bonding network across the dimer interface. These studies revealed several previously unknown interactions and critical residues predicted to impact VP40 dimer formation. In vitro and cellular studies were then pursued for a subset of VP40 mutations demonstrating reduction in dimer formation (in vitro) or plasma membrane localization (in cells). Together, the computational and experimental approaches revealed critical residues for VP40 dimer stability in an alpha-helical interface (between residues 106-117) as well as in a loop region (between residues 52-61) below this alpha-helical region. This study sheds light on the structural origins of VP40 dimer formation and may inform the design of a small molecule that can disrupt VP40 dimer stability.

The potential risk components and prevention measures of the Ebola virus disease outbreak in Liberia: An in-depth interview with the health workers and stakeholders.

Background: The Ebola virus, a highly infectious and deadly pathogen, has posed a significant public health threat in West Africa for several decades. Liberia is one of the most severely affected countries. Healthcare personnel, including nurses, are on the front lines of patient care, and their perspectives are invaluable in understanding the challenges that arise during outbreaks, especially in implementing prevention measures. Objective: This study aimed to explore the potential risk components and prevention measures of the Ebola virus disease (EVD). Methods: This study used an exploratory descriptive qualitative design. Five stakeholders, ten doctors and five nurses who had suffered from EVD during the outbreak in Liberia participated in semi-structured interviews to provide their experience and comprehensive perspectives on EVD. Data were collected from February 2022-August 2023. NVivo 12 plus was used for inductive thematic analysis. Results: Six themes and several subthemes emerged: 1) transmission modes (body contact, body fluid, sexual intercourse, traditional burial), 2) funeral attendance (traditional practices and crowded gatherings), 3) community-led prevention (promoting good hygiene practices, increasing awareness, contact tracing, and surveillance), 4) Ebola virus vaccine (false sense of security, potential side effects, and limited data), 5) challenges in implementing prevention measures (inadequate health infrastructures, difficulty of tracing infected people, lack of resources, and cultural-social barriers), 6) Liberia's health systems (a weak, underfunded, fragile health infrastructure, lack of health facilities and shortage of health workers). Conclusion: Several potential risk components contributing to the EVD outbreak should be a public concern. Strengthening the current healthcare system supported by local community and international aid providers (multidisciplinary teams) is needed to anticipate behavioral problems and to improve the efficacy of the prevention measures appropriate to the conditions in Liberia. Accordingly, the nurses' compliance with the recommended prevention practices is necessary.

Childhood vision impairment and blindness in West Africa: public health measures and implications for systemic health.

Childhood blindness is an issue of global health impact, affecting approximately 2 million children worldwide. Vision 2020 and the United Nations Sustainable Development Goals previously identified childhood blindness as a key issue in the twentieth century, and while public health measures are underway, the precise etiologies and management require ongoing investigation and care, particularly within resource-limited settings such as sub-Saharan Africa. We systematically reviewed the literature on childhood blindness in West Africa to identify the anatomic classification and etiologies, particularly those causes of childhood blindness with systemic health implications. Treatable causes included cataract, refractive error, and corneal disease. Systemic etiologies identified included measles, rubella, vitamin A deficiency, and Ebola virus disease. While prior public health measures including vitamin A supplementation and vaccination programs have been deployed in most countries with reported data, multiple studies reported preventable or reversible etiologies of blindness and vision impairment. Ongoing research is necessary to standardize reporting for anatomies and/or etiologies of childhood blindness to determine the necessity of further development and implementation of public health measures that would ameliorate childhood blindness and vision impairment.