Ebola vaccine--an urgent international priority

Exploring the therapeutic potential of galidesivir analogs against Zaire ebolavirus protein 24 (V24): database screening, molecular docking, drug-relevant property evaluation and molecular dynamics simulations

The recent outbreak of the Ebola virus (EBOV) has marked it as one of the most severe health threats globally. Among various anti-EBOV inhibitors studied, galidesivir (BCX4430) has shown remarkable efficacy. This study aims to identify novel potential anti-EBOV drugs among galidesivir analogs, focusing on the Zaire ebolavirus (Z-EBOV), which exhibits a mortality rate of 90%. We subjected 200 candidate compounds to molecular docking calculations, followed by an evaluation of the bioactivity of the top 25 compounds using the OSIRIS Property Explorer. Initial 50 ns molecular dynamics (MD) simulations were then performed. According to our findings, only six compounds exhibited positive drug scores. We further performed molecular mechanics Poisson-Boltzmann surface area (MM/PBSA) calculations of binding energy over 50 ns, selecting the two top-performing compounds for extended 150 ns MD simulations. CID 117698807 and CID 117712809 showed higher binding stability compared to galidesivir, with ΔGbinding values of -36.7 and -53.4 kcal/mol, respectively. Both compounds demonstrated high stability within the Z-EBOV-V24 active site over the 150 ns MD simulations. Hence, our study proposes CID 117698807 and CID 117712809 as potential anti-Z-EBOV-V24 drug candidates, warranting further investigation.Communicated by Ramaswamy H. Sarma.

Global blood miRNA profiling unravels early signatures of immunogenicity of Ebola vaccine rVSVΔG-ZEBOV-GP

The vectored Ebola vaccine rVSVΔG-ZEBOV-GP elicits protection against Ebola Virus Disease (EVD). In a study of forty-eight healthy adult volunteers who received either the rVSVΔG-ZEBOV-GP vaccine or placebo, we profiled intracellular microRNAs (miRNAs) from whole blood cells (WB) and circulating miRNAs from serum-derived extracellular vesicles (EV) at baseline and longitudinally following vaccination. Further, we identified early miRNA signatures associated with ZEBOV-specific IgG antibody responses at baseline and up to one year post-vaccination, and pinpointed target mRNA transcripts and pathways correlated to miRNAs whose expression was altered after vaccination by using systems biology approaches. Several miRNAs were differentially expressed (DE) and miRNA signatures predicted high or low IgG ZEBOV-specific antibody levels with high classification performance. The top miRNA discriminators were WB-miR-6810, EV-miR-7151-3p, and EV-miR-4426. An eight-miRNA antibody predictive signature was associated with immune-related target mRNAs and pathways. These findings provide valuable insights into early blood biomarkers associated with rVSVΔG-ZEBOV-GP vaccine-induced IgG antibody responses.

Sudan virus disease outbreak in Uganda in 2022: the case of patient zero

In 2000, Uganda reported the first Ebola disease outbreak, and since then, the nation has had several other outbreaks. CASE PRESENTATION: On September 15, 2022, a Ugandan man aged 24 years presented with a history of fever, hematemesis, and hematochezia. A clinical suspicion of a viral hemorrhagic fever was raised, the patient was isolated, and the authorities were notified. Clinical samples subjected to real-time polymerase chain reaction analysis confirmed Sudan virus disease (SVD) caused by the Sudan Ebola virus species. The patient died 3 days later. By November 30, 2022, there had been a total of 142 confirmed cases of SVD in Uganda, with 56 (39.4%) fatalities. The case described in this report is the first patient who was hospitalized during this outbreak. CONCLUSIONS: SVD has a high mortality rate despite the best supportive management. Therefore, it is important to focus on preventive measures to control outbreaks of this disease.

The ring vaccination trial design for the estimation of vaccine efficacy and effectiveness during infectious disease outbreaks

The ring vaccination trial is a recently developed approach for evaluating the efficacy and effectiveness of vaccines, modeled after the surveillance and containment strategy of ring vaccination. Contacts and contacts of contacts of a newly identified disease case form a ring, and these rings are randomized as part of a cluster-randomized trial or with individual randomization within rings. Key advantages of the design include its flexibility to follow the epidemic as it progresses and the targeting of high-risk participants to increase power. We describe the application of the design to estimate the efficacy and effectiveness of an Ebola vaccine during the 2014-2016 West African Ebola epidemic. The design has several notable statistical features. Because vaccination occurs around the time of exposure, the design is particularly sensitive to the choice of per protocol analysis period. If incidence wanes before the per protocol analysis period begins (due to a slow-acting vaccine or a fast-moving pathogen), power can be substantially reduced. Mathematical modeling is valuable for exploring the suitability of the approach in different disease settings. Another statistical feature is zero inflation, which can occur if the chain of transmission does not take off within a ring. In the application to Ebola, the majority of rings had zero subsequent cases. The ring vaccination trial can be extended in several ways, including the definition of rings (e.g. contact-based, spatial, and occupational). The design will be valuable in settings where the spatio-temporal spread of the pathogen is highly focused and unpredictable.

Implementation of accelerated research: strategies for implementation as applied in a phase 1 Ad26.ZEBOV, MVA-BN-Filo two-dose Ebola vaccine clinical trial in Uganda

Background

The 2013–2016 Ebola epidemic in West Africa is the worst ever caused by Ebolaviruses with over 28,000 human cases and 11,325 deaths. The World Health Organisation (WHO) declared the epidemic a public health crisis that required accelerated development of novel interventions including vaccines. The Medical Research Council/Uganda Virus Research Institute and London School of Hygiene and Tropical Medicine Uganda Research Unit (MRC/UVRI & LSHTM Uganda Research Unit) was among the African research sites that implemented the VAC52150EBL1004 Ebola vaccine trial.

Objective

We report on the strategies utilised by the Unit and sponsor in ensuring expedited clinical trial approval and accelerated conduct.

Methods

Janssen Vaccines and Prevention B.V. conducted a phase 1 trial to evaluate the safety, tolerability, and immunogenicity of heterologous two-dose vaccination regimens using Ad26.ZEBOV and MVA-BN-Filo, in healthy adults in Africa. Accelerated implementation strategies are hereby presented.

Results

Strategies included: holding the African Vaccine Regulatory Forum (AVAREF) joint review meeting; expedited review by institutional ethics and country-specific regulatory bodies; competitive recruitment between sites; electronic data capture (EDC); frequent study monitoring schedule; involvement of a community advisory board (CAB); and utilization of a ‘phased’ study information-sharing approach in community engagement and participant recruitment. These strategies enabled the site to acquire approvals within 2 months and enrol 47 participants within a spurn of five. The same milestone is usually acquired in at least 1 year without accelerated implementation.

Conclusion

The use of well-thought strategies by sponsors and research sites can enable the implementation of accelerated research. We recommend the use of similar strategies in other settings.

Ebolavirus: Comparison of Survivor Immunology and Animal Models in the Search for a Correlate of Protection

Ebola viruses are enveloped, single-stranded RNA viruses belonging to the Filoviridae family and can cause Ebola virus disease (EVD), a serious haemorrhagic illness with up to 90% mortality. The disease was first detected in Zaire (currently the Democratic Republic of Congo) in 1976. Since its discovery, Ebola virus has caused sporadic outbreaks in Africa and was responsible for the largest 2013-2016 EVD epidemic in West Africa, which resulted in more than 28,600 cases and over 11,300 deaths. This epidemic strengthened international scientific efforts to contain the virus and develop therapeutics and vaccines. Immunology studies in animal models and survivors, as well as clinical trials have been crucial to understand Ebola virus pathogenesis and host immune responses, which has supported vaccine development. This review discusses the major findings that have emerged from animal models, studies in survivors and vaccine clinical trials and explains how these investigations have helped in the search for a correlate of protection.

No Evidence of rVSV-Ebola Virus Vaccine Replication or Dissemination in the Sand Fly Phlebotomus papatasi

Following vaccination with the live attenuated, recombinant vesicular stomatitis virus Indiana serotype Ebola virus (rVSV-EBOV) vaccine, persons may exhibit a transient vaccine-associated viremia. To investigate the potential for Old World sand flies to transmit this vaccine following feeding on a viremic person, we fed laboratory-reared Phlebotomus papatasi an artificial blood meal containing 7.2 log10 plaque-forming units of rVSV-EBOV. Replication or dissemination was not detected in the body or legs of any P. papatasi collected at seven (n = 75) or 15 (n = 75) days post-feed. These results indicate a low potential for rVSV-EBOV to replicate and disseminate in P. papatasi, a species whose geographic distribution ranges from Morocco to southwest Asia and as far north as southern Europe.

Exploiting the reverse vaccinology approach to design novel subunit vaccines against Ebola virus

Ebola virus is a highly pathogenic RNA virus that causes the Ebola haemorrhagic fever in human. This virus is considered as one of the dangerous viruses in the world with very high mortality rate. To date, no epitope-based subunit vaccine has yet been discovered to fight against Ebola although the outbreaks of this deadly virus took many lives in the past. In this study, approaches of reverse vaccinology were utilized in combination with different tools of immunoinformatics to design subunit vaccines against Ebola virus strain Mayinga-76. Three potential antigenic proteins of this virus i.e., matrix protein VP40, envelope glycoprotein and nucleoprotein were selected to construct the subunit vaccine. The MHC class-I, MHC class-II and B-cell epitopes were determined initially and after some robust analysis i.e., antigenicity, allergenicity, toxicity, conservancy and molecular docking study, EV-1, EV-2 and EV-3 were constructed as three potential vaccine constructs. These vaccine constructs are also expected to be effective on few other strains of Ebola virus since the highly conserved epitopes were used for vaccine construction. Thereafter, molecular docking study was conducted on these vaccines and EV-1 emerged as the best vaccine construct. Afterward, molecular dynamics simulation study revealed the good performances and stability of the intended vaccine protein. Finally, codon adaptation and in silico cloning were carried out to design a possible plasmid (pET-19b plasmid vector was used) for large scale production of the EV-1 vaccine. However, further in vitro and in vivo studies might be required on the predicted vaccines for final validation.

Human Antibody Repertoire following Ebola Virus Infection and Vaccination

Limited knowledge exists on the quality of polyclonal antibody response generated following Ebola virus (EBOV) infection compared with vaccination. Polyclonal antibody repertoire in plasma following EBOV infection in survivors was compared with ChAd3-MVA prime-boost human vaccination. Higher antibody binding and affinity to GP was observed in survivors compared with vaccinated plasma that correlated with EBOV neutralization. Surprisingly, a predominant IgM response was generated after prime-boost vaccination, whereas survivors demonstrated IgG-dominant antibody response. EBOV infection induced more diverse antibody epitope repertoire compared with vaccination. A strong binding to antigenic sites in the fusion peptide and another in the highly conserved GP2-HR2 domain was preferentially recognized by EBOV survivors than vaccinated individuals that correlated strongly with EBOV neutralization titers. These findings will help development and evaluation of effective Ebola countermeasures including therapeutics and vaccines.

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EBOV infection induced a more diverse antibody repertoire than vaccination

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Ebola survivors demonstrated long-lasting, high-affinity, IgG antibody response

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Several novel antigenic sites recognized by post-EBOV infection sera

The NCATS Pharmaceutical Collection: a 10-year update

The National Center for Advancing Translational Sciences (NCATS) Pharmaceutical Collection (NPC), a comprehensive collection of clinically approved drugs, was made a public resource in 2011. Over the past decade, the NPC has been systematically profiled for activity across an array of pathways and disease models, generating an unparalleled amount of data. These data have not only enabled the identification of new repurposing candidates with several in clinical trials, but also uncovered new biological insights into drug targets and disease mechanisms. This retrospective provides an update on the NPC in terms of both successes and lessons learned. We also report our efforts in bringing the NPC up-to-date with drugs approved in recent years.

A Role for Fc Function in Therapeutic Monoclonal Antibody-Mediated Protection against Ebola Virus

The recent Ebola virus (EBOV) epidemic highlighted the need for effective vaccines and therapeutics to limit and prevent outbreaks. Host antibodies against EBOV are critical for controlling disease, and recombinant monoclonal antibodies (mAbs) can protect from infection. However, antibodies mediate an array of antiviral functions including neutralization as well as engagement of Fc-domain receptors on immune cells, resulting in phagocytosis or NK cell-mediated killing of infected cells. Thus, to understand the antibody features mediating EBOV protection, we examined specific Fc features associated with protection using a library of EBOV-specific mAbs. Neutralization was strongly associated with therapeutic protection against EBOV. However, several neutralizing mAbs failed to protect, while several non-neutralizing or weakly neutralizing mAbs could protect. Antibody-mediated effector functions, including phagocytosis and NK cell activation, were associated with protection, particularly for antibodies with moderate neutralizing activity. This framework identifies functional correlates that can inform therapeutic and vaccine design strategies against EBOV and other pathogens.

Advances in Designing and Developing Vaccines, Drugs, and Therapies to Counter Ebola Virus

Ebola virus (EBOV), a member of the family Filoviridae, is responsible for causing Ebola virus disease (EVD) (formerly named Ebola hemorrhagic fever). This is a severe, often fatal illness with mortality rates varying from 50 to 90% in humans. Although the virus and associated disease has been recognized since 1976, it was only when the recent outbreak of EBOV in 2014-2016 highlighted the danger and global impact of this virus, necessitating the need for coming up with the effective vaccines and drugs to counter its pandemic threat. Albeit no commercial vaccine is available so far against EBOV, a few vaccine candidates are under evaluation and clinical trials to assess their prophylactic efficacy. These include recombinant viral vector (recombinant vesicular stomatitis virus vector, chimpanzee adenovirus type 3-vector, and modified vaccinia Ankara virus), Ebola virus-like particles, virus-like replicon particles, DNA, and plant-based vaccines. Due to improvement in the field of genomics and proteomics, epitope-targeted vaccines have gained top priority. Correspondingly, several therapies have also been developed, including immunoglobulins against specific viral structures small cell-penetrating antibody fragments that target intracellular EBOV proteins. Small interfering RNAs and oligomer-mediated inhibition have also been verified for EVD treatment. Other treatment options include viral entry inhibitors, transfusion of convalescent blood/serum, neutralizing antibodies, and gene expression inhibitors. Repurposed drugs, which have proven safety profiles, can be adapted after high-throughput screening for efficacy and potency for EVD treatment. Herbal and other natural products are also being explored for EVD treatment. Further studies to better understand the pathogenesis and antigenic structures of the virus can help in developing an effective vaccine and identifying appropriate antiviral targets. This review presents the recent advances in designing and developing vaccines, drugs, and therapies to counter the EBOV threat.

Measles-derived vaccines to prevent emerging viral diseases

Infectious disease epidemics match wars and natural disasters in their capacity to threaten lives and damage economies. Like SARS previously and Zika recently, the Ebola crisis in 2015 showed how vulnerable the world is to these epidemics, with over 11,000 people dying in the outbreak. In addition to causing immense human suffering, these epidemics particularly affect low- and middle-income countries. Many of these deadly infectious diseases that have epidemic potential can become global health emergencies in the absence of effective vaccines. But very few vaccines against these threats have been developed to create proven medical products. The measles vaccine is an efficient, live attenuated, replicating virus that has been safely administered to 2 billion children over the last 40 years, affording life-long protection after a single dose. Taking advantage of these characteristics, this attenuated virus was transformed into a versatile chimeric or recombinant vaccine vector with demonstrated proof-of-principle in humans and a preclinical track record of rapid adaptability and effectiveness for a variety of pathogens. Clinical trials have shown the safety and immunogenicity of this vaccine platform in individuals with preexisting immunity to measles. This review describes the potential of this platform to develop new vaccines against emerging viral diseases.

A Serological Point-of-Care Test for the Detection of IgG Antibodies against Ebola Virus in Human Survivors

Ebola virus disease causes widespread and highly fatal epidemics in human populations. Today, there is still great need for point-of-care tests for diagnosis, patient management and surveillance, both during and post outbreaks. We present a point-of-care test comprising an immunochromatographic strip and a smartphone reader, which detects and semiquantifies Ebola-specific antibodies in human survivors. We developed a Sudan virus glycoprotein monoplex platform and validated it using sera from 90 human survivors and 31 local noninfected controls. The performance of the glycoprotein monoplex was 100% sensitivity and 98% specificity compared to standard whole antigen enzyme-linked immunosorbent assay (ELISA), and it was validated with freshly collected patient samples in Uganda. Moreover, we constructed a multiplex test for simultaneous detection of antibodies against three recombinant Sudan virus proteins. A pilot study comprising 15 survivors and 5 noninfected controls demonstrated sensitivity and specificity of 100% compared to standard ELISA. Finally, we developed a second multiplex subtype assay for the identification of exposure to three related EVD species: Sudan virus, Bundibugyo virus and Ebola virus (formerly Zaire) using recombinant viral glycoprotein. This multiplex test could distinguish between the host's immunity to specific viral species and identify cross-reactive immunity. These developed serological platforms consisted of capture ligands with high specificity and sensitivity, in-house developed strips and a compatible smartphone application. These platforms enabled rapid and portable testing, data storage and sharing as well as geographical tagging of the tested individuals in Uganda. This platform holds great potential as a field tool for diagnosis, vaccine development, and therapeutic evaluation.

Safety and immunogenicity of rVSVΔG-ZEBOV-GP Ebola vaccine in adults and children in Lambaréné, Gabon: A phase I randomised trial

BACKGROUND

The rVSVΔG-ZEBOV-GP vaccine prevented Ebola virus disease when used at 2 × 107 plaque-forming units (PFU) in a trial in Guinea. This study provides further safety and immunogenicity data.

METHODS AND FINDINGS

A randomised, open-label phase I trial in Lambaréné, Gabon, studied 5 single intramuscular vaccine doses of 3 × 103, 3 × 104, 3 × 105, 3 × 106, or 2 × 107 PFU in 115 adults and a dose of 2 × 107 PFU in 20 adolescents and 20 children. The primary objective was safety and tolerability 28 days post-injection. Immunogenicity, viraemia, and shedding post-vaccination were evaluated as secondary objectives. In adults, mild-to-moderate adverse events were frequent, but there were no serious or severe adverse events related to vaccination. Before vaccination, Zaire Ebola virus (ZEBOV)-glycoprotein (GP)-specific and ZEBOV antibodies were detected in 11% and 27% of adults, respectively. In adults, 74%-100% of individuals who received a dose 3 × 104, 3 × 105, 3 × 106, or 2 × 107 PFU had a ≥4.0-fold increase in geometric mean titres (GMTs) of ZEBOV-GP-specific antibodies at day 28, reaching GMTs of 489 (95% CI: 264-908), 556 (95% CI: 280-1,101), 1,245 (95% CI: 899-1,724), and 1,503 (95% CI: 931-2,426), respectively. Twenty-two percent of adults had a ≥4-fold increase of ZEBOV antibodies, with GMTs at day 28 of 1,015 (647-1,591), 1,887 (1,154-3,085), 1,445 (1,013-2,062), and 3,958 (2,249-6,967) for the same doses, respectively. These antibodies persisted up to day 180 for doses ≥3 × 105 PFU. Adults with antibodies before vaccination had higher GMTs throughout. Neutralising antibodies were detected in more than 50% of participants at doses ≥3 × 105 PFU. As in adults, no serious or severe adverse events related to vaccine occurred in adolescents or children. At day 2, vaccine RNA titres were higher for adolescents and children than adults. At day 7, 78% of adolescents and 35% of children had recombinant vesicular stomatitis virus RNA detectable in saliva. The vaccine induced high GMTs of ZEBOV-GP-specific antibodies at day 28 in adolescents, 1,428 (95% CI: 1,025-1,989), and children, 1,620 (95% CI: 806-3,259), and in both groups antibody titres increased up to day 180. The absence of a control group, lack of stratification for baseline antibody status, and imbalances in male/female ratio are the main limitations of this study.

CONCLUSIONS

Our data confirm the acceptable safety and immunogenicity profile of the 2 × 107 PFU dose in adults and support consideration of lower doses for paediatric populations and those who request boosting.

TRIAL REGISTRATION

Pan African Clinical Trials Registry PACTR201411000919191.

A heterologous prime-boost Ebola virus vaccine regimen induces durable neutralizing antibody response and prevents Ebola virus-like particle entry in mice

Ebola virus (EBOV) is one of the most virulent pathogens known to humans. Neutralizing antibodies play a major role in the protection against EBOV infections. Thus, an EBOV vaccine capable of inducing a long-lasting neutralizing antibody response is highly desirable. We report here that a heterologous prime-boost vaccine regimen can elicit durable EBOV-neutralizing antibody response in mice. A chimpanzee serotype 7 adenovirus expressing EBOV GP (denoted AdC7-GP) was generated and used for priming. A truncated version of EBOV GP1 protein (denoted GP1t) was produced at high levels in Drosophila S2 cells and used for boosting. Mouse immunization studies showed that the AdC7-GP prime/GP1t boost vaccine regimen was more potent in eliciting neutralizing antibodies than either the AdC7-GP or GP1t alone. Neutralizing antibodies induced by the heterologous prime-boost regimen sustained at high titers for at least 18 weeks after immunization. Significantly, in vivo challenge studies revealed that the entry of reporter EBOV-like particles was efficiently blocked in mice receiving the heterologous prime-boost regimen even at 18 weeks after the final dose of immunization. These results suggest that this novel AdC7-GP prime/GP1t boost regimen represents an EBOV vaccine approach capable of establishing long-term protection, and therefore warrants further development.

Assessing the safety and immunogenicity of recombinant vesicular stomatitis virus Ebola vaccine in healthy adults: a randomized clinical trial

BACKGROUND

The 2013-2016 Ebola virus outbreak in West Africa was the most widespread in history. In response, alive attenuated recombinant vesicular stomatitis virus (rVSV) vaccine expressing Zaire Ebolavirus glycoprotein (rVSVΔG-ZEBOV-GP) was evaluated in humans.

METHODS

In a phase 1, randomized, dose-ranging, observer-blind, placebo-controlled trial, healthy adults aged 18-65 years were randomized into 4 groups of 10 to receive one of 3 vaccine doses or placebo. Follow-up visits spanned 180 days postvaccination for safety monitoring, immunogenicity testing and any rVSV virus shedding.

RESULTS

Forty participants were injected with rVSVΔG-ZEBOV-GP vaccine (n = 30) or saline placebo (n = 10). No serious adverse events related to the vaccine or participant withdrawals were reported. Solicited adverse events during the 14-day follow-up period were mild to moderate and self-limited, with the exception of injection-site pain and headache. Viremia following vaccination was transient and no longer detectable after study day 3, with no virus shedding in saliva or urine. All vaccinated participants developed serum immunoglobulin G (IgG), as measured by Ebola virus envelope glycoprotein-based enzyme-linked immunosorbent assay (ELISA). Immunogenicity was comparable across all dose groups, and sustained IgG titers were detectable through to the last visit, at study day 180.

INTERPRETATION

In this phase 1 study, there were no safety concerns after a single dose of rVSVΔG-ZEBOV-GP vaccine. IgG ELISA showed persistent high titers at 180 days postimmunization. There was a period of reactogenicity, but in general, the vaccine was well tolerated. This study provides evidence of the safety and immunogenicity of rVSVΔG-ZEBOV-GP vaccine and importance of its further investigation. Trial registration: Clinical-Trials.gov no., NCT02374385.

The state of gene therapy research in Africa, its significance and implications for the future

Gene therapy has made impressive recent progress and has potential for treating a wide range of diseases, many of which are important to Africa. However, as a result of lack of direct public funding and skilled personnel, direct research on gene therapy in Africa is currently limited and resources to support the endeavor are modest. A strength of the technology is that it is based on principles of rational design, and the tools of gene therapy are now highly versatile. For example gene silencing and gene editing may be used to disable viral genes for therapeutic purposes. Gene therapy may thus lead to cure from infections with HIV-1, hepatitis B virus and Ebola virus, which are of significant public health importance in Africa. Although enthusiasm for gene therapy is justified, significant challenges to implementing the technology remain. These include ensuring efficient delivery of therapeutic nucleic acids to target cells, limiting unintended effects, cost and complexity of treatment regimens. In addition, implementation of effective legislation that will govern gene therapy research will be a challenge. Nevertheless, it is an exciting prospect that gene therapy should soon reach the mainstream of medical management. Participation of African researchers in the exciting developments is currently limited, but their involvement is important to address health problems, develop capacity and enhance economic progress of the continent.

A dose-dependent plasma signature of the safety and immunogenicity of the rVSV-Ebola vaccine in Europe and Africa

The 2014-2015 Ebola epidemic affected several African countries, claiming more than 11,000 lives and leaving thousands with ongoing sequelae. Safe and effective vaccines could prevent or limit future outbreaks. The recombinant vesicular stomatitis virus-vectored Zaire Ebola (rVSV-ZEBOV) vaccine has shown marked immunogenicity and efficacy in humans but is reactogenic at higher doses. To understand its effects, we examined plasma samples from 115 healthy volunteers from Geneva who received low-dose (LD) or high-dose (HD) vaccine or placebo. Fifteen plasma chemokines/cytokines were assessed at baseline and on days 1, 2 to 3, and 7 after injection. Significant increases in monocyte-mediated MCP-1/CCL2, MIP-1β/CCL4, IL-6, TNF-α, IL-1Ra, and IL-10 occurred on day 1. A signature explaining 68% of cytokine/chemokine vaccine-response variability was identified. Its score was higher in HD versus LD vaccinees and was associated positively with vaccine viremia and negatively with cytopenia. It was higher in vaccinees with injection-site pain, fever, myalgia, chills, and headache; higher scores reflected increasing severity. In contrast, HD vaccinees who subsequently developed arthritis had lower day 1 scores than other HD vaccinees. Vaccine dose did not influence the signature despite its influence on specific outcomes. The Geneva-derived signature associated strongly (ρ = 0.97) with that of a cohort of 75 vaccinees from a parallel trial in Lambaréné, Gabon. Its score in Geneva HD vaccinees with subsequent arthritis was significantly lower than that in Lambaréné HD vaccinees, none of whom experienced arthritis. This signature, which reveals monocytes' critical role in rVSV-ZEBOV immunogenicity and safety across doses and continents, should prove useful in assessments of other vaccines.

Immunomonitoring of human responses to the rVSV-ZEBOV Ebola vaccine

The rVSV-ZEBOV vaccine is currently the only Ebola vaccine with demonstrated clinical efficacy in a ring-vaccination clinical trial. It has been shown to be reactogenic but immunogenic and safe in several Phase I clinical studies. However, its mechanisms of protection are unknown and available immunogenicity data are mostly limited to classical serological analysis; it is now of paramount importance to apply cutting-edge technologies, including transcriptomic and metabolomic analyses, and to perform integrative analyses with standard serology and clinical data to comprehensively profile the rVSV-ZEBOV immune signature.

Efficacy and effectiveness of an rVSV-vectored vaccine in preventing Ebola virus disease: final results from the Guinea ring vaccination, open-label, cluster-randomised trial (Ebola Ça Suffit!)

BACKGROUND

rVSV-ZEBOV is a recombinant, replication competent vesicular stomatitis virus-based candidate vaccine expressing a surface glycoprotein of Zaire Ebolavirus. We tested the effect of rVSV-ZEBOV in preventing Ebola virus disease in contacts and contacts of contacts of recently confirmed cases in Guinea, west Africa.

METHODS

We did an open-label, cluster-randomised ring vaccination trial (Ebola ça Suffit!) in the communities of Conakry and eight surrounding prefectures in the Basse-Guinée region of Guinea, and in Tomkolili and Bombali in Sierra Leone. We assessed the efficacy of a single intramuscular dose of rVSV-ZEBOV (2×107 plaque-forming units administered in the deltoid muscle) in the prevention of laboratory confirmed Ebola virus disease. After confirmation of a case of Ebola virus disease, we definitively enumerated on a list a ring (cluster) of all their contacts and contacts of contacts including named contacts and contacts of contacts who were absent at the time of the trial team visit. The list was archived, then we randomly assigned clusters (1:1) to either immediate vaccination or delayed vaccination (21 days later) of all eligible individuals (eg, those aged ≥18 years and not pregnant, breastfeeding, or severely ill). An independent statistician generated the assignment sequence using block randomisation with randomly varying blocks, stratified by location (urban vs rural) and size of rings (≤20 individuals vs >20 individuals). Ebola response teams and laboratory workers were unaware of assignments. After a recommendation by an independent data and safety monitoring board, randomisation was stopped and immediate vaccination was also offered to children aged 6-17 years and all identified rings. The prespecified primary outcome was a laboratory confirmed case of Ebola virus disease with onset 10 days or more from randomisation. The primary analysis compared the incidence of Ebola virus disease in eligible and vaccinated individuals assigned to immediate vaccination versus eligible contacts and contacts of contacts assigned to delayed vaccination. This trial is registered with the Pan African Clinical Trials Registry, number PACTR201503001057193.

FINDINGS

In the randomised part of the trial we identified 4539 contacts and contacts of contacts in 51 clusters randomly assigned to immediate vaccination (of whom 3232 were eligible, 2151 consented, and 2119 were immediately vaccinated) and 4557 contacts and contacts of contacts in 47 clusters randomly assigned to delayed vaccination (of whom 3096 were eligible, 2539 consented, and 2041 were vaccinated 21 days after randomisation). No cases of Ebola virus disease occurred 10 days or more after randomisation among randomly assigned contacts and contacts of contacts vaccinated in immediate clusters versus 16 cases (7 clusters affected) among all eligible individuals in delayed clusters. Vaccine efficacy was 100% (95% CI 68·9-100·0, p=0·0045), and the calculated intraclass correlation coefficient was 0·035. Additionally, we defined 19 non-randomised clusters in which we enumerated 2745 contacts and contacts of contacts, 2006 of whom were eligible and 1677 were immediately vaccinated, including 194 children. The evidence from all 117 clusters showed that no cases of Ebola virus disease occurred 10 days or more after randomisation among all immediately vaccinated contacts and contacts of contacts versus 23 cases (11 clusters affected) among all eligible contacts and contacts of contacts in delayed plus all eligible contacts and contacts of contacts never vaccinated in immediate clusters. The estimated vaccine efficacy here was 100% (95% CI 79·3-100·0, p=0·0033). 52% of contacts and contacts of contacts assigned to immediate vaccination and in non-randomised clusters received the vaccine immediately; vaccination protected both vaccinated and unvaccinated people in those clusters. 5837 individuals in total received the vaccine (5643 adults and 194 children), and all vaccinees were followed up for 84 days. 3149 (53·9%) of 5837 individuals reported at least one adverse event in the 14 days after vaccination; these were typically mild (87·5% of all 7211 adverse events). Headache (1832 [25·4%]), fatigue (1361 [18·9%]), and muscle pain (942 [13·1%]) were the most commonly reported adverse events in this period across all age groups. 80 serious adverse events were identified, of which two were judged to be related to vaccination (one febrile reaction and one anaphylaxis) and one possibly related (influenza-like illness); all three recovered without sequelae.

INTERPRETATION

The results add weight to the interim assessment that rVSV-ZEBOV offers substantial protection against Ebola virus disease, with no cases among vaccinated individuals from day 10 after vaccination in both randomised and non-randomised clusters.

FUNDING

WHO, UK Wellcome Trust, the UK Government through the Department of International Development, Médecins Sans Frontières, Norwegian Ministry of Foreign Affairs (through the Research Council of Norway's GLOBVAC programme), and the Canadian Government (through the Public Health Agency of Canada, Canadian Institutes of Health Research, International Development Research Centre and Department of Foreign Affairs, Trade and Development).

Ebola Vaccination Using a DNA Vaccine Coated on PLGA-PLL/γPGA Nanoparticles Administered Using a Microneedle Patch

Ebola DNA vaccine is incorporated into PLGA-PLL/γPGA nanoparticles and administered to skin using a microneedle (MN) patch. The nanoparticle delivery system increases vaccine thermostability and immunogenicity compared to free vaccine. Vaccination by MN patch produces stronger immune responses than intramuscular administration.

Deciphering assumptions about stepped wedge designs: the case of Ebola vaccine research

Ethical concerns about randomising persons to a no-treatment arm in the context of Ebola epidemic led to consideration of alternative designs. The stepped wedge (SW) design, in which participants or clusters are randomised to receive an intervention at different time points, gained popularity. Common arguments in favour of using this design are (1) when an intervention is likely to do more good than harm, (2) all participants should receive the experimental intervention at some time point during the study and (3) the design might be preferable for practical reasons. We examine these assumptions when considering Ebola vaccine research. First, based on the claim that a stepped wedge design is indicated when it is likely that the intervention will do more good than harm, we reviewed published and ongoing SW trials to explore previous use of this design to test experimental drugs or vaccines, and found that SW design has never been used for trials of experimental drugs or vaccines. Given that Ebola vaccines were all experimental with no prior efficacy data, the use of a stepped wedge design would have been unprecedented. Second, we show that it is rarely true that all participants receive the intervention in SW studies, but rather, depending on certain design features, all clusters receive the intervention. Third, we explore whether the SW design is appealing for feasibility reasons and point out that there is significant complexity. In the setting of the Ebola epidemic, spatiotemporal variation may have posed problematic challenges to a stepped wedge design for vaccine research. Finally, we propose a set of points to consider for scientific reviewers and ethics committees regarding proposals for SW designs.

Human antibody repertoire after VSV-Ebola vaccination identifies novel targets and virus-neutralizing IgM antibodies

Development of an effective vaccine against Ebola virus is of high priority. However, knowledge about potential correlates of protection and the durability of immune response after vaccination is limited. Here, we elucidate the human antibody repertoire after administration of vesicular stomatitis virus (VSV)-Ebola vaccine at 3 million, 20 million and 100 million plaque-forming units (PFU) and homologous VSV-Ebola vaccine boost in healthy adult volunteers. Whole genome-fragment phage display libraries, expressing linear and conformational epitopes of Ebola glycoprotein (GP), showed higher diversity of antibody epitopes in individuals vaccinated with 20 million PFU than in those vaccinated with 3 million or 100 million PFU. Surface plasmon resonance kinetics showed higher levels of GP-binding antibodies after a single vaccination with 20 million or 100 million PFU than with 3 million PFU, and these correlated strongly with neutralization titers. A second vaccination did not boost antibody or virus neutralization titers, which declined rapidly, and induced only minimal antibody affinity maturation. Isotype analysis revealed a predominant IgM response even after the second vaccination, which contributed substantially to virus neutralization in vitro. These findings may help identify new vaccine targets and aid development and evaluation of effective countermeasures against Ebola.

Ebola vaccine R&D: Filling the knowledge gaps

With an emphasis on systems analyses, the VSV-EBOVAC project harnesses state-of-the-art technologies that illuminate mechanisms behind the observed immunogenicity and reactogenicity of the rVSV-ZEBOV vaccine and ensures that such information is shared among stakeholders.

Critical role of ethics in clinical management and public health response to the West Africa Ebola epidemic

The devastation caused by the Ebola virus disease (EVD) outbreak in West Africa has brought to the fore a number of important ethical debates about how best to respond to a health crisis. These debates include issues related to prevention and containment, management of the health care workforce, clinical care, and research design, all of which are situated within the overarching moral problem of severe transnational disadvantage, which has very real and specific impacts upon the ability of citizens of EVD-affected countries to respond to a disease outbreak. Ethical issues related to prevention and containment include the appropriateness and scope of quarantine and isolation within and outside affected countries. The possibility of infection in health care workers impelled consideration of whether there is an obligation to provide health services where personal protection equipment is inadequate, alongside the issue of whether the health care workforce should have special access to experimental treatment and care interventions under development. In clinical care, ethical issues include the standards of care owed to people who comply with quarantine and isolation restrictions. Ethical issues in research include appropriate study design related to experimental vaccines and treatment interventions, and the sharing of data and biospecimens between research groups. The compassionate use of experimental drugs intersects both with research ethics and clinical care. The role of developed countries also came under scrutiny, and we concluded that developed countries have an obligation to contribute to the containment of EVD infection by contributing to the strengthening of local health care systems and infrastructure in an effort to provide fair benefits to communities engaged in research, ensuring that affected countries have ready and affordable access to any therapeutic or preventative interventions developed, and supporting affected countries on their way to recovery from the impact of EVD on their social and economic lives.

On a path to accelerate access to Ebola vaccines: The WHO's research and development efforts during the 2014-2016 Ebola epidemic in West Africa

During 2014 and 2015 an outbreak of Ebola deemed a Public Health Emergency of International Concern affected a number of West African countries. The outbreak underscored the need for a vaccine against Ebola. An unprecedented and to great extent collaborative effort built on the availability of a number of candidate vaccines that could enter into clinical phase evaluation. A series of international consultations and activities were led by WHO as a contribution to the unprecedented global efforts to develop and assess an Ebola vaccine. WHO consulted widely, and immediately fostered interactions with the international scientific, ethics, regulatory, vaccine development, public health partners, industry and funders' communities and participated in consortia to facilitate Ebola vaccine assessments. WHO also fostered key activities to ensure the optimal policy and deployment of Ebola vaccines, if licensed. WHO has convened a broad global coalition of experts to develop a Blueprint and a platform for accelerated R&D, in order to avert full-blown epidemics.

Phase 1 Trials of rVSV Ebola Vaccine in Africa and Europe

BACKGROUND

The replication-competent recombinant vesicular stomatitis virus (rVSV)-based vaccine expressing a Zaire ebolavirus (ZEBOV) glycoprotein was selected for rapid safety and immunogenicity testing before its use in West Africa.

METHODS

We performed three open-label, dose-escalation phase 1 trials and one randomized, double-blind, controlled phase 1 trial to assess the safety, side-effect profile, and immunogenicity of rVSV-ZEBOV at various doses in 158 healthy adults in Europe and Africa. All participants were injected with doses of vaccine ranging from 300,000 to 50 million plaque-forming units (PFU) or placebo.

RESULTS

No serious vaccine-related adverse events were reported. Mild-to-moderate early-onset reactogenicity was frequent but transient (median, 1 day). Fever was observed in up to 30% of vaccinees. Vaccine viremia was detected within 3 days in 123 of the 130 participants (95%) receiving 3 million PFU or more; rVSV was not detected in saliva or urine. In the second week after injection, arthritis affecting one to four joints developed in 11 of 51 participants (22%) in Geneva, with pain lasting a median of 8 days (interquartile range, 4 to 87); 2 self-limited cases occurred in 60 participants (3%) in Hamburg, Germany, and Kilifi, Kenya. The virus was identified in one synovial-fluid aspirate and in skin vesicles of 2 other vaccinees, showing peripheral viral replication in the second week after immunization. ZEBOV-glycoprotein-specific antibody responses were detected in all the participants, with similar glycoprotein-binding antibody titers but significantly higher neutralizing antibody titers at higher doses. Glycoprotein-binding antibody titers were sustained through 180 days in all participants.

CONCLUSIONS

In these studies, rVSV-ZEBOV was reactogenic but immunogenic after a single dose and warrants further evaluation for safety and efficacy. (Funded by the Wellcome Trust and others; ClinicalTrials.gov numbers, NCT02283099, NCT02287480, and NCT02296983; Pan African Clinical Trials Registry number, PACTR201411000919191.).

The Ethics of Infection Challenges in Primates

In the midst of the recent Ebola outbreak, scientific developments involving infection challenge experiments on nonhuman primates (NHPs) sparked hope that successful treatments and vaccines may soon become available. Yet these studies pose a stark ethical quandary. On the one hand, they represent an important step in developing novel therapies and vaccines for Ebola and the Marburg virus, with the potential to save thousands of human lives and to protect whole communities from devastation; on the other hand, they intentionally expose sophisticated animals to severe suffering and a high risk of death. Other studies that infect NHPs with a lethal disease in order to test interventions that may prove beneficial for humans pose the same ethical difficulty. Some advocates have argued that all research on primates should be phased out, and ethicists have questioned whether a moral justification of primate research is possible. A 2010 European Union directive banned virtually all research on great apes, and 2013 guidelines from the National Institutes of Health (NIH), based upon recommendations in an influential 2011 Institute of Medicine (IOM) report, eliminated most biomedical research with chimpanzees in the United States. But studies involving other NHPs face no comparable restrictions. Should research on NHPs other than great apes be subject to tighter restrictions than it currently is? In this article, we explore this general question in the context of one particular type of biomedical research: infection challenge studies. We advocate a presumptive prohibition on infection challenge experiments in NHPs, but we also argue that exceptions to this prohibition are permissible, subject to strict substantive and procedural safeguards, when necessary to avert substantial loss of human life or severe morbidity for a substantial number of people.

A vaccine against Ebola: Problems and opportunities

The unprecedented dimensions of the 2014 Ebola epidemic which ravaged 3 West African countries have challenged public health response capacity and urged the availability of safe and effective vaccines. In this context, vectored vaccines already tested in animal models have undergone phase 1 studies in human beings and are now ready for efficacy evaluation in large scale trials. Health care workers and other frontline caregivers are likely to be the target population for both vaccine trials and vaccination campaigns. However, methodological and ethical issues should be considered in plans concerning the conduction of clinical trials and the possible use of licensed vaccines against Ebola.

Ebola vaccine development plan: ethics, concerns and proposed measures

BACKGROUND

The global interest in developing therapies for Ebola infection management and its prevention is laudable. However the plan to conduct an emergency immunization program specifically for healthcare workers using experimental vaccines raises some ethical concerns. This paper shares perspectives on these concerns and suggests how some of them may best be addressed.

DISCUSSION

The recruitment of healthcare workers for Ebola vaccine research has challenges. It could result in coercion of initially dissenting healthcare workers to assist in the management of EVD infected persons due to mistaken beliefs that the vaccine offers protection. It could also affect equity and justice. For example, where people who are not skilled health care professionals but who provide care to patients infected with Ebola (such as in home care settings) are not prioritized for vaccination. The possibility of study participants contracting Ebola infection despite the use of experimental vaccine, and the standard of care they would receive, needs to be addressed clearly, transparently and formalized as part of the ethics review process. Future access to study products in view of current status of the TRIPS agreement needs to be addressed. Finally, broad stakeholder engagement at local, regional and international levels needs to be promoted using available communication channels to engage local, regional and international support. These same concerns are applicable for current and future epidemics. Successful Ebola vaccine development research requires concerted efforts at public dialogue to address misconceptions, equity and justice in participant selection, and honest discussions about risks, benefits and future access. Public dialogue about Ebola vaccine research plans is crucial and should be conducted by trusted locals and negotiated between communities, researchers and ethics committees in research study sites.

Ethical Rationale for the Ebola "Ring Vaccination" Trial Design

The 2014 Ebola virus epidemic is the largest and most severe ever recorded. With no approved vaccines or specific treatments for Ebola, clinical trials were launched within months of the epidemic in an unprecedented show of global partnership. One of these trials used a highly innovative "ring vaccination" design. The design was chosen for operational, scientific, and ethical reasons--in particular, it was regarded as ethically superior to individually randomized placebo-controlled trials. We scrutinize the ethical rationale for the ring vaccination design. We argue that the ring vaccination design is ethical but fundamentally equivalent to placebo-controlled designs with respect to withholding a potentially effective intervention from the control group. We discuss the implications for the ongoing ring vaccination trial and future research.

Towards detection and diagnosis of Ebola virus disease at point-of-care

Ebola outbreak-2014 (mainly Zaire strain related Ebola virus) has been declared most widely spread deadly persistent epidemic due to unavailability of rapid diagnostic, detection, and therapeutics. Ebola virus disease (EVD), a severe viral hemorrhagic fever syndrome caused by Ebola virus (EBOV) is transmitted by direct contact with the body fluids of infected person and objects contaminated with virus or infected animals. World Health Organization (WHO) has declared EVD epidemic as public health emergency of international concern with severe global economic burden. At fatal EBOV infection stage, patients usually die before the antibody response. Currently, rapid blood tests to diagnose EBOV infection include the antigen or antibodies capture using ELISA and RNA detection using RT/Q-PCR within 3-10 days after the onset of symptoms. Moreover, few nanotechnology-based colorimetric and paper-based immunoassay methods have been recently reported to detect Ebola virus. Unfortunately, these methods are limited to laboratory only. As state-of-the art (SoA) diagnostics time to confirm Ebola infection, varies from 6h to about 3 days, it causes delay in therapeutic approaches. Thus developing a cost-effective, rapid, sensitive, and selective sensor to detect EVD at point-of-care (POC) is certainly worth exploring to establish rapid diagnostics to decide therapeutics. This review highlights SoA of Ebola diagnostics and also a call to develop rapid, selective and sensitive POC detection of EBOV for global health care. We propose that adopting miniaturized electrochemical EBOV immunosensing can detect virus level at pM concentration within ∼40min compared to 3 days of ELISA test at nM levels.

Use of ChAd3-EBO-Z Ebola virus vaccine in Malian and US adults, and boosting of Malian adults with MVA-BN-Filo: a phase 1, single-blind, randomised trial, a phase 1b, open-label and double-blind, dose-escalation trial, and a nested, randomised, double-blind, placebo-controlled trial

BACKGROUND

The 2014 west African Zaire Ebola virus epidemic prompted worldwide partners to accelerate clinical development of replication-defective chimpanzee adenovirus 3 vector vaccine expressing Zaire Ebola virus glycoprotein (ChAd3-EBO-Z). We aimed to investigate the safety, tolerability, and immunogenicity of ChAd3-EBO-Z in Malian and US adults, and assess the effect of boosting of Malians with modified vaccinia Ankara expressing Zaire Ebola virus glycoprotein and other filovirus antigens (MVA-BN-Filo).

METHODS

In the phase 1, single-blind, randomised trial of ChAd3-EBO-Z in the USA, we recruited adults aged 18-65 years from the University of Maryland medical community and the Baltimore community. In the phase 1b, open-label and double-blind, dose-escalation trial of ChAd3-EBO-Z in Mali, we recruited adults 18-50 years of age from six hospitals and health centres in Bamako (Mali), some of whom were also eligible for a nested, randomised, double-blind, placebo-controlled trial of MVA-BN-Filo. For randomised segments of the Malian trial and for the US trial, we randomly allocated participants (1:1; block size of six [Malian] or four [US]; ARB produced computer-generated randomisation lists; clinical staff did randomisation) to different single doses of intramuscular immunisation with ChAd3-EBO-Z: Malians received 1 × 10(10) viral particle units (pu), 2·5 × 10(10) pu, 5 × 10(10) pu, or 1 × 10(11) pu; US participants received 1 × 10(10) pu or 1 × 10(11) pu. We randomly allocated Malians in the nested trial (1:1) to receive a single dose of 2 × 10(8) plaque-forming units of MVA-BN-Filo or saline placebo. In the double-blind segments of the Malian trial, investigators, clinical staff, participants, and immunology laboratory staff were masked, but the study pharmacist (MK), vaccine administrator, and study statistician (ARB) were unmasked. In the US trial, investigators were not masked, but participants were. Analyses were per protocol. The primary outcome was safety, measured with occurrence of adverse events for 7 days after vaccination. Both trials are registered with ClinicalTrials.gov, numbers NCT02231866 (US) and NCT02267109 (Malian).

FINDINGS

Between Oct 8, 2014, and Feb 16, 2015, we randomly allocated 91 participants in Mali (ten [11%] to 1 × 10(10) pu, 35 [38%] to 2·5 × 10(10) pu, 35 [38%] to 5 × 10(10) pu, and 11 [12%] to 1 × 10(11) pu) and 20 in the USA (ten [50%] to 1 × 10(10) pu and ten [50%] to 1 × 10(11) pu), and boosted 52 Malians with MVA-BN-Filo (27 [52%]) or saline (25 [48%]). We identified no safety concerns with either vaccine: seven (8%) of 91 participants in Mali (five [5%] received 5 × 10(10) and two [2%] received 1 × 10(11) pu) and four (20%) of 20 in the USA (all received 1 × 10(11) pu) given ChAd3-EBO-Z had fever lasting for less than 24 h, and 15 (56%) of 27 Malians boosted with MVA-BN-Filo had injection-site pain or tenderness.

INTERPRETATION

1 × 10(11) pu single-dose ChAd3-EBO-Z could suffice for phase 3 efficacy trials of ring-vaccination containment needing short-term, high-level protection to interrupt transmission. MVA-BN-Filo boosting, although a complex regimen, could confer long-lived protection if needed (eg, for health-care workers).

FUNDING

Wellcome Trust, Medical Research Council UK, Department for International Development UK, National Cancer Institute, Frederick National Laboratory for Cancer Research, Federal Funds from National Institute of Allergy and Infectious Diseases.

The Ebola Vaccine Team B: a model for promoting the rapid development of medical countermeasures for emerging infectious disease threats

In support of accelerated development of Ebola vaccines from preclinical research to clinical trials, in November, 2014, the Wellcome Trust and the Center for Infectious Disease Research and Policy (CIDRAP) at the University of Minnesota established the Wellcome Trust-CIDRAP Ebola Vaccine Team B initiative. This ongoing initiative includes experts with global experience in various phases of bringing new vaccines to market, such as funding, research and development, manufacturing, determination of safety and efficacy, regulatory approval, and vaccination delivery. It also includes experts in community engagement strategies and ethical issues germane to vaccination policies, including eight African scientists with direct experience in developing and implementing vaccination policies in Africa. Ebola Vaccine Team B members have worked on a range of vaccination programmes, such as polio eradication (Africa and globally), development of meningococcal A disease vaccination campaigns in Africa, and malaria and HIV/AIDS vaccine research. We also provide perspective on how this experience can inform future situations where urgent development of vaccines is needed, and we comment on the role that an independent, expert group such as Team B can have in support of national and international public health authorities toward addressing a public health crisis.

Recent advances in the development of vaccines for Ebola virus disease

Ebola virus is one of the most dangerous microorganisms in the world causing hemorrhagic fevers in humans and non-human primates. Ebola virus (EBOV) is a zoonotic infection, which emerges and re-emerges in human populations. The 2014 outbreak was caused by the Zaire strain, which has a kill rate of up to 90%, though 40% was recorded in the current outbreak. The 2014 outbreak is larger than all 20 outbreaks that have occurred since 1976, when the virus was first discovered. It is the first time that the virus was sustained in urban centers and spread beyond Africa into Europe and USA. Thus far, over 22,000 cases have been reported with about 50% mortality in one year. There are currently no approved therapeutics and preventive vaccines against Ebola virus disease (EVD). Responding to the devastating effe1cts of the 2014 outbreak and the potential risk of global spread, has spurred research for the development of therapeutics and vaccines. This review is therefore aimed at presenting the progress of vaccine development. Results showed that conventional inactivated vaccines produced from EBOV by heat, formalin or gamma irradiation appear to be ineffective. However, novel vaccines production techniques have emerged leading to the production of candidate vaccines that have been demonstrated to be effective in preclinical trials using small animal and non-human primates (NHP) models. Some of the promising vaccines have undergone phase 1 clinical trials, which demonstrated their safety and immunogenicity. Many of the candidate vaccines are vector based such as Vesicular Stomatitis Virus (VSV), Rabies Virus (RABV), Adenovirus (Ad), Modified Vaccinia Ankara (MVA), Cytomegalovirus (CMV), human parainfluenza virus type 3 (HPIV3) and Venezuelan Equine Encephalitis Virus (VEEV). Other platforms include virus like particle (VLP), DNA and subunit vaccines.

Ethical considerations in the conduct of research on therapies for the prevention and treatment of Ebola virus disease in developing countries

The devastating toll of the Ebola epidemic in West Africa necessitates considerations of new approaches to research into new prevention technologies and treatments for Ebola Virus Disease (EVD). Research must be planned and delivered in consultation with civil society from the epicentre to prevent mistrust and misunderstanding. Ethical considerations include development of local research and regulatory capacity; negotiating the standard of prevention packages for research participants, including healthcare workers; and strengthening health systems in developing countries to ensure effective response to future EVD outbreaks in the region. Also, strategic consultation with local communities is an ethical imperative for EVD research, particularly where there is potential for differential access to prevention and care packages between trial staff and local hospital staff.

New paradigms in sepsis: from prevention to protection of failing microcirculation

Sepsis, also known as septicemia, is one of the 10 leading causes of death worldwide. The rising tide of sepsis due to bacterial, fungal and viral infections cannot be stemmed by current antimicrobial therapies and supportive measures. New paradigms for the mechanism and resolution of sepsis and consequences for sepsis survivors are emerging. Consistent with Benjamin Franklin's dictum 'an ounce of prevention is worth a pound of cure', sepsis can be prevented by vaccinations against pneumococci and meningococci. Recently, the NIH NHLBI Panel redefined sepsis as 'severe endothelial dysfunction syndrome in response to intravascular and extravascular infections causing reversible or irreversible injury to the microcirculation responsible for multiple organ failure'. Microvascular endothelial injury underlies sepsis-associated hypotension, edema, disseminated intravascular coagulation, acute respiratory distress syndrome and acute kidney injury. Microbial genome products trigger 'genome wars' in sepsis that reprogram the human genome and culminate in a 'genomic storm' in blood and vascular cells. Sepsis can be averted experimentally by endothelial cytoprotection through targeting nuclear signaling that mediates inflammation and deranged metabolism. Endothelial 'rheostats' (e.g. inhibitors of NF-κB, A20 protein, CRADD/RAIDD protein and microRNAs) regulate endothelial signaling. Physiologic 'extinguishers' (e.g. suppressor of cytokine signaling 3) can be replenished through intracellular protein therapy. Lipid mediators (e.g. resolvin D1) hasten sepsis resolution. As sepsis cases rose from 387 330 in 1996 to 1.1 million in 2011, and are estimated to reach 2 million by 2020 in the US, mortality due to sepsis approaches that of heart attacks and exceeds deaths from stroke. More preventive vaccines and therapeutic measures are urgently needed.

Efficacy and effectiveness of an rVSV-vectored vaccine expressing Ebola surface glycoprotein: interim results from the Guinea ring vaccination cluster-randomised trial

BACKGROUND

A recombinant, replication-competent vesicular stomatitis virus-based vaccine expressing a surface glycoprotein of Zaire Ebolavirus (rVSV-ZEBOV) is a promising Ebola vaccine candidate. We report the results of an interim analysis of a trial of rVSV-ZEBOV in Guinea, west Africa.

METHODS

For this open-label, cluster-randomised ring vaccination trial, suspected cases of Ebola virus disease in Basse-Guinée (Guinea, west Africa) were independently ascertained by Ebola response teams as part of a national surveillance system. After laboratory confirmation of a new case, clusters of all contacts and contacts of contacts were defined and randomly allocated 1:1 to immediate vaccination or delayed (21 days later) vaccination with rVSV-ZEBOV (one dose of 2 × 10(7) plaque-forming units, administered intramuscularly in the deltoid muscle). Adults (age ≥18 years) who were not pregnant or breastfeeding were eligible for vaccination. Block randomisation was used, with randomly varying blocks, stratified by location (urban vs rural) and size of rings (≤20 vs >20 individuals). The study is open label and masking of participants and field teams to the time of vaccination is not possible, but Ebola response teams and laboratory workers were unaware of allocation to immediate or delayed vaccination. Taking into account the incubation period of the virus of about 10 days, the prespecified primary outcome was laboratory-confirmed Ebola virus disease with onset of symptoms at least 10 days after randomisation. The primary analysis was per protocol and compared the incidence of Ebola virus disease in eligible and vaccinated individuals in immediate vaccination clusters with the incidence in eligible individuals in delayed vaccination clusters. This trial is registered with the Pan African Clinical Trials Registry, number PACTR201503001057193.

FINDINGS

Between April 1, 2015, and July 20, 2015, 90 clusters, with a total population of 7651 people were included in the planned interim analysis. 48 of these clusters (4123 people) were randomly assigned to immediate vaccination with rVSV-ZEBOV, and 42 clusters (3528 people) were randomly assigned to delayed vaccination with rVSV-ZEBOV. In the immediate vaccination group, there were no cases of Ebola virus disease with symptom onset at least 10 days after randomisation, whereas in the delayed vaccination group there were 16 cases of Ebola virus disease from seven clusters, showing a vaccine efficacy of 100% (95% CI 74·7-100·0; p=0·0036). No new cases of Ebola virus disease were diagnosed in vaccinees from the immediate or delayed groups from 6 days post-vaccination. At the cluster level, with the inclusion of all eligible adults, vaccine effectiveness was 75·1% (95% CI -7·1 to 94·2; p=0·1791), and 76·3% (95% CI -15·5 to 95·1; p=0·3351) with the inclusion of everyone (eligible or not eligible for vaccination). 43 serious adverse events were reported; one serious adverse event was judged to be causally related to vaccination (a febrile episode in a vaccinated participant, which resolved without sequelae). Assessment of serious adverse events is ongoing.

INTERPRETATION

The results of this interim analysis indicate that rVSV-ZEBOV might be highly efficacious and safe in preventing Ebola virus disease, and is most likely effective at the population level when delivered during an Ebola virus disease outbreak via a ring vaccination strategy.

FUNDING

WHO, with support from the Wellcome Trust (UK); Médecins Sans Frontières; the Norwegian Ministry of Foreign Affairs through the Research Council of Norway; and the Canadian Government through the Public Health Agency of Canada, Canadian Institutes of Health Research, International Development Research Centre, and Department of Foreign Affairs, Trade and Development.

A tug-of-war between the host and the pathogen generates strategic hotspots for the development of novel therapeutic interventions against infectious diseases

Microbial pathogens are known to express an array of specific signaling molecules referred as Pathogen Associated Molecular Patterns (PAMPs), which are recognized by Pattern Recognition Receptors (PRRs), present on the surface of the host cells. Interactions between PAMPs and PRRs on the surface of the host cells lead to signaling events which could culminate into either successful infection or clearance of the pathogens. Here, we summarize how these events may generate novel host based as well as pathogen based molecular targets for designing effective therapeutic strategies against infections.

Against the clock towards new Ebola virus therapies

Since the end of 2013, West Africa has been suffering the largest Ebola virus (EBOV) outbreak in recorded history. The lack of health care infrastructure in the affected countries, as well as a concentration of infected cases in the most populated areas allowed the virus to spread with no control during the first months of the outbreak. With no specific treatment available to combat EBOV infection and its associated disease, an extraordinary worldwide effort was made to confront the severity of the situation and to establish new therapeutic strategies that would lead to better and faster control and eradicate the outbreak. In the last two years, several candidate therapies and potential vaccines against EBOV have arisen and human clinical trials are ongoing, in hopes of starting their deployment in the affected countries. This article reviews the current candidate therapies against EBOV, their stage of development and future prospects in battling EBOV outbreaks.

Pastoral care of patients with Ebola Virus Disease: A medical and canonical opinion about pastoral visits to patients with contagious and highly fatal diseases

The Ebola Virus Disease is a contagious and highly fatal illness that up until recently had been geographically limited to remote areas of Africa. In 2014, Ebola patients have been transported to the United States for care or have been newly diagnosed in the United States. With the intensive medical care and isolation policies usually needed by these patients, we inquired whether pastoral care would be possible. Using clinical and canonical considerations, we analyzed the permissibility and logistical challenges pastoral care presents to the priests and lay ministers, as well as the healthcare system. We conclude that with the approval of local, state, and federal health officials, pastoral care, including provision of the sacraments, is possible. It would require proper training, proper equipment and policies, and a significant commitment of time. While the risk to the pastoral team is difficult to define, it seems low in an Ebola-capable medical system. These risks to priests and ministers seem reasonable given the inestimable benefits of receiving the sacraments during critical illness. Lay summary: Traditional pastoral visits to hospitalized patients might prove difficult or impossible for diseases that are contagious and highly fatal. This inquiry examines the feasibility, challenges, and logistical solutions to these visits. With input from bishops, priests, a canon lawyer, an epidemiologist, a physician, the CDC, and others, we conclude that pastoral visits are possible. Visits will require permission of health authorities, commitments of time, training, and a small but significant risk to the health of priests and others who volunteer for this ministry.