Pharmacokinetics of Ribavirin in the Treatment of Lassa Fever: An Observational Clinical Study at the Irrua Specialist Teaching Hospital, Edo State, Nigeria.

BACKGROUND: Lassa fever is endemic in large parts of West Africa. The recommended antiviral treatment is ribavirin. Two treatment regimens are currently endorsed in Nigeria: the "McCormick regimen" based on a study published in 1986 and the "Irrua regimen" constituting a simplified schedule developed at the Irrua Specialist Teaching Hospital, Nigeria. Evidence for the safety and efficacy of ribavirin in Lassa fever patients is poor and pharmacokinetic data for both regimens are lacking. METHODS: Polymerase chain reaction-confirmed Lassa fever patients with mild to moderate disease severity were invited to participate in this prospective, observational pharmacokinetic study. Pharmacokinetics of ribavirin, clinical, virologic, and clinical laboratory parameters were assessed. RESULTS: Using a population pharmacokinetic approach, plasma concentrations of ribavirin were best described by a 3-compartment model. Drug exposure was remarkably consistent between participants. Overall, drug clearance was 28.5% lower in female compared with male participants. Median (5th-95th percentile) time above half maximal inhibitory concentration (IC50) was 37.3% (16.9%-73.1%), 16.7% (8.2%-58.5%), and 9.6% (4.9%-38.4%) on days 1, 7, and 8, respectively. Clinical laboratory parameters indicated reduction of cell damage and development of hemolytic anemia in the course of the treatment period. CONCLUSIONS: This observational study characterizes the pharmacokinetics of ribavirin in the treatment of Lassa fever indicating consistent exposure across patients. Whereas only a short time interval of concentrations above the IC50 implies rather low antiviral efficacy in vivo, the prominent reduction of cell damage markers might point to indirect-potentially anti-inflammatory-effects of ribavirin. The role of ribavirin in the treatment of Lassa fever requires further scrutiny.

High burden of RSV and influenza in patients presenting with suspected pneumonia in the emergency room of a German tertiary hospital in fall of 2022.

PURPOSE: Bacterial pneumonia, a major cause of respiratory tract infections (RTI), can be challenging to diagnose and to treat adequately, especially when seasonal viral pathogens co-circulate. The aim of this study was to give a real-world snapshot of the burden of respiratory disease and treatment choices in the emergency department (ED) of a tertiary care hospital in Germany in the fall of 2022. METHODS: Anonymized analysis of a quality control initiative that prospectively documented all patients presenting to our ED with symptoms suggestive of RTI from Nov 7th to Dec 18th, 2022. RESULTS: 243 patients were followed at the time of their ED attendance. Clinical, laboratory and radiographic examination was performed in 92% of patients (224/243). Microbiological work-up to identify causative pathogens including blood cultures, sputum or urine-antigen tests were performed in 55% of patients (n = 134). Detection of viral pathogens increased during the study period from 7 to 31 cases per week, while bacterial pneumonias, respiratory tract infections without detection of a viral pathogen and non-infectious etiologies remained stable. A high burden of bacterial and viral co-infections became apparent (16%, 38/243), and co-administration of antibiotic and antiviral treatments was observed (14%, n = 35/243). 17% of patients (41/243) received antibiotic coverage without a diagnosis of a bacterial etiology. CONCLUSION: During the fall of 2022, the burden of RTI caused by detectable viral pathogens increased unusually early. Rapid and unexpected changes in pathogen distribution highlight the need for targeted diagnostics to improve the quality of RTI management in the ED.

The COVID-19 Vaccine Landscape.

The history of vaccine development spans centuries. At first, whole pathogens were used as vaccine agents, either inactivated or attenuated, to reduce virulence in humans. Safety and tolerability were increased by including only specific proteins as antigens and using cell culture methods, while novel vaccine strategies, like nucleic acid- or vector-based vaccines, hold high promise for the future. Vaccines have generally not been employed as the primary tools in outbreak response, but this might change since advances in medical technology in the last decades have made the concept of developing vaccines against novel pathogens a realistic strategy. Wandering the uncharted territory of a novel pathogen, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we can learn from other human Betacoronaviridae that emerged in the last decades, SARS-CoV-1 and MERS-CoV. We can identify the most likely target structures of immunity, establish animal models that emulate human disease and immunity as closely as possible, and learn about complex mechanisms of immune interaction such as cross-reactivity or antibody-dependent enhancement (ADE). However, significant knowledge gaps remain. What are the correlates of protection? How do we best induce immunity in vulnerable populations like the elderly? Will the immunity induced by vaccination (or by natural infection) wane over time? To date, at least 149 vaccine candidates against SARS-CoV-2 are under development. At the time of writing, at least 17 candidates have already progressed past preclinical studies (in vitro models and in vivo animal experiments) into clinical development. This chapter will provide an overview of this rapidly developing field.

[Mild COVID-19 disease in healthcare workers at a German university clinic : The "first wave" at the University Medical Center Hamburg-Eppendorf]. / Milde COVID-19-Verläufe bei Mitarbeitenden einer Universitätsklinik : Die "erste Welle" am Universitätsklinikum Hamburg-Eppendorf.

BACKGROUND: Healthcare workers are among the most exposed and potentially most threatened populations of the ongoing COVID-19 pandemic. Despite some reports on numbers of infections with SARS-CoV­2 in German healthcare workers, the courses of their clinical presentation when affected by COVID-19 are not well described. OBJECTIVE: In this contribution, characteristics and progressions of infected cases among healthcare workers at the University Medical Center Hamburg-Eppendorf during the first wave of the COVID-19 pandemic will be presented. METHODS: Between 1 July and 28 July 2020, 67 healthcare workers, who previously tested positive for SARS-CoV­2 via PCR, were invited via E­mail to participate in an anonymous online questionnaire; 39 persons participated. RESULTS: Participants (58%) were mostly ≤ 39 years old (64%) and female (70%). Most healthcare workers were involved in direct patient management (85%), including contact with SARS-CoV­2 positive patients (62%). All participants reported acute symptoms with a median duration of 19 days. The most frequent symptoms were fatigue (85%), anosmia (67%), cough (64%), headache (62%), and shortness of breath (51%). The disease course was mostly mild with low admission rates (5%). Ongoing symptoms lasting more than four weeks post-symptom-onset, particularly anosmia, fatigue, and shortness of breath, were reported by 38%. This group more frequently had pre-existing conditions (53% vs. 12%, p = 0.010), specifically hypertension (27% vs. 4%, p = 0.062). DISCUSSION: Healthcare workers reported mostly mild courses of COVID-19 despite increased contact with SARS-CoV-2 patients. However, some reported persistent symptoms months after infection.

[Vaccination against RSV infections - update and perspective]. / Impfung gegen RSV-Infektionen ­ Update und Ausblick.

Almost 60 years after a disastrous clinical vaccine trial in children, which resulted in enhanced disease and even deaths, the world of RSV vaccination is currently undergoing a dramatic positive change and development, closely linked to advances in new vaccine technologies. Three licensed safe and highly efficacious vaccines, Abrysvo, Arexvy and mRESVIA, reduce the incidence of RSV lower respiratory disease by 80% in people older than 60 years of age. Questions regarding long-term protection and effectiveness in specific risk groups with chronic medical conditions remain, and furthermore, innovative and safe concepts to actively vaccinate pregnant women and infants to prevent severe RSV infections - also in these high-risk populations - are eagerly awaited.Passive vaccination with the long-acting monoclonal antibody Nirsevimab for prevention of severe disease in the first RSV season of infants is a major innovation in global health and the importance and benefits of reducing the number of intramuscular injections for high-risk children is immense. In the coming years, results of numerous pediatric candidate RSV vaccine studies are expected, although particular caution seems advisable for historical reasons. In summary, the field of RSV vaccination has been revolutionized in the last 2 years and we will see further significant progress soon.

[Vaccinations for emerging and re-emerging viral diseases]. / Impfungen für neu- und wiederauftretende Viruserkrankungen.

BACKGROUND: Emerging or re-emerging viral diseases have a pandemic potential and threaten global health. Vaccination is of crucial importance in the prevention of emerging and re-emerging viral diseases. OBJECTIVE: Description of the current status of vaccine development against Filoviridae, highly pathogenic coronaviruses, smallpox viruses, influenza viruses and arboviruses. MATERIAL AND METHODS: Focused literature search. RESULTS: The World Health Organization (WHO) regularly publishes a list of infectious diseases that are expected to pose a major threat to humanity as they are could potentially trigger new pandemics; however, in addition to these human-to-human transmissible diseases, some arboviruses also have pandemic potential. In recent years numerous new vaccines, some of which are highly effective, have been licensed against new and re-emerging viral diseases and other promising vaccine candidates are currently in development. CONCLUSION: There are still gaps in the development of vaccines in the area of Filoviridae and highly pathogenic coronaviruses. Vaccinations against smallpox viruses have been available for a long time. Developing influenza vaccines against novel strains in a timely manner is a challenge and universal influenza vaccines could be a possible solution. Modern vaccines are available against the arboviruses dengue and Chikungunya fever.

Dissecting humoral immune responses to an MVA-vectored MERS-CoV vaccine in humans using a systems serology approach.

Besides neutralizing antibodies, which are considered an important measure for vaccine immunogenicity, Fc-mediated antibody functions can contribute to antibody-mediated protection. They are strongly influenced by structural antibody properties such as subclass and Fc glycan composition. We here applied a systems serology approach to dissect humoral immune responses induced by MVA-MERS-S, an MVA-vectored vaccine against the Middle East respiratory syndrome coronavirus (MERS-CoV). Building on preceding studies reporting the safety and immunogenicity of MVA-MERS-S, our study highlights the potential of a late boost, administered one year after prime, to enhance both neutralizing and Fc-mediated antibody functionality compared to the primary vaccination series. Distinct characteristics were observed for antibodies specific to the MERS-CoV spike protein S1 and S2 subunits, regarding subclass and glycan compositions as well as Fc functionality. These findings highlight the benefit of a late homologous booster vaccination with MVA-MERS-S and may be of interest for the design of future coronavirus vaccines.

Antibody-dependent cellular cytotoxicity in patients on chronic hemodialysis.

BACKGROUND: Antibody (Ab)-dependent cellular cytotoxicity (ADCC) is considered to be a relevant mechanism of action of Ab-based tumor therapies. However, knowledge about ADCC capacity of dialysis patients (DP) is limited. The aim of our study was to investigate if ADCC capacity of effector cells obtained from DP differed from those of healthy individuals (HI). METHODS: First, we performed ADCC assays with isolated polymorphonuclear cells (PMN) and peripheral blood mononuclear cells (PBMC), mediated by the epidermal growth factor receptor Ab cetuximab or panitumumab. As cetuximab is of human IgG1 and panitumumab of human IgG2 isotype, both Abs differ in their affinity to Fcγ receptors and effector cell recruitment. RESULTS: Using PMN as effectors, ADCC levels via panitumumab proved to be higher than via cetuximab, but did not differ between DP and HI. In contrast, IgG2-mediated ADCC with PBMC from DP was significantly enhanced compared to HI. IgG2 Abs predominantly bind to FcγRIIa. Within the PBMC, monocytes are the only cytotoxic cells physiologically expressing this receptor. ADCC experiments with isolated monocytes confirmed them to be the pivotal cells for the observed effect. Analysis of monocytes' Fc receptor expression demonstrated no difference between DP and HI, but monocytes of DP proved to be numerically increased and appeared preactivated. CONCLUSION: Our studies implicate that ADCC capacity is not impaired in DP and that it might particularly be reasonable to apply human IgG2 Abs as therapeutics for these patients.

Focussed Assessment with Sonography in acute Lassa Fever (FASLa): Development of a point-of-care protocol and description of common ultrasound findings.

BACKGROUND: Managing Lassa fever (LF) patients is challenging because of the complexity of this life-threatening infectious disease, the necessary isolation measures, and the limited resources in countries where it is endemic. Point-of-care ultrasonography (POCUS) is a promising low-cost imaging technique that may help in guiding the management of patients. METHODS: We conducted this observational study at the Irrua Specialist Teaching Hospital in Nigeria. We developed a POCUS protocol, trained local physicians who applied the protocol to LF patients and recorded and interpreted the clips. These were then independently re-evaluated by an external expert, and associations with clinical, laboratory and virological data were analyzed. FINDINGS: We developed the POCUS protocol based on existing literature and expert opinion and trained two clinicians, who then used POCUS to examine 46 patients. We observed at least one pathological finding in 29 (63%) patients. Ascites was found in 14 (30%), pericardial effusion in 10 (22%), pleural effusion in 5 (11%), and polyserositis in 7 (15%) patients, respectively. Eight patients (17%) showed hyperechoic kidneys. Seven patients succumbed to the disease while 39 patients survived, resulting in a fatality rate of 15%. Pleural effusions and hyper-echoic kidneys were associated with increased mortality. INTERPRETATION: In acute LF, a newly established POCUS protocol readily identified a high prevalence of clinically relevant pathological findings. The assessment by POCUS required minimal resources and training; the detected pathologies such as pleural effusions and kidney injury may help to guide the clinical management of the most at-risk LF patients.

Persistence of MERS-CoV-spike-specific B cells and antibodies after late third immunization with the MVA-MERS-S vaccine.

The Middle East respiratory syndrome (MERS) is a respiratory disease caused by MERS coronavirus (MERS-CoV). In follow up to a phase 1 trial, we perform a longitudinal analysis of immune responses following immunization with the modified vaccinia virus Ankara (MVA)-based vaccine MVA-MERS-S encoding the MERS-CoV-spike protein. Three homologous immunizations were administered on days 0 and 28 with a late booster vaccination at 12 ± 4 months. Antibody isotypes, subclasses, and neutralization capacity as well as T and B cell responses were monitored over a period of 3 years using standard and bead-based enzyme-linked immunosorbent assay (ELISA), 50% plaque-reduction neutralization test (PRNT50), enzyme-linked immunospot (ELISpot), and flow cytometry. The late booster immunization significantly increases the frequency and persistence of spike-specific B cells, binding immunoglobulin G1 (IgG1) and neutralizing antibodies but not T cell responses. Our data highlight the potential of a late boost to enhance long-term antibody and B cell immunity against MERS-CoV. Our findings on the MVA-MERS-S vaccine may be of relevance for coronavirus 2019 (COVID-19) vaccination strategies.

Increased neutralization and IgG epitope identification after MVA-MERS-S booster vaccination against Middle East respiratory syndrome.

Vaccine development is essential for pandemic preparedness. We previously conducted a Phase 1 clinical trial of the vector vaccine candidate MVA-MERS-S against the Middle East respiratory syndrome coronavirus (MERS-CoV), expressing its full spike glycoprotein (MERS-CoV-S), as a homologous two-dose regimen (Days 0 and 28). Here, we evaluate the safety (primary objective) and immunogenicity (secondary and exploratory objectives: magnitude and characterization of vaccine-induced humoral responses) of a third vaccination with MVA-MERS-S in a subgroup of trial participants one year after primary immunization. MVA-MERS-S booster vaccination is safe and well-tolerated. Both binding and neutralizing anti-MERS-CoV antibody titers increase substantially in all participants and exceed maximum titers observed after primary immunization more than 10-fold. We identify four immunogenic IgG epitopes, located in the receptor-binding domain (RBD, n = 1) and the S2 subunit (n = 3) of MERS-CoV-S. The level of baseline anti-human coronavirus antibody titers does not impact the generation of anti-MERS-CoV antibody responses. Our data support the rationale of a booster vaccination with MVA-MERS-S and encourage further investigation in larger trials. Trial registration: Clinicaltrials.gov NCT03615911.

Correlates of Vaccine-Induced Protection against SARS-CoV-2.

We are in the midst of a pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes the coronavirus disease 2019 (COVID-19). SARS-CoV-2 has caused more than two million deaths after one year of the pandemic. The world is experiencing a deep economic recession. Safe and effective vaccines are needed to prevent further morbidity and mortality. Vaccine candidates against COVID-19 have been developed at an unprecedented speed, with more than 200 vaccine candidates currently under investigation. Among those, 20 candidates have entered the clinical Phase 3 to evaluate efficacy, and three have been approved by the European Medicines Agency. The aim of immunization is to act against infection, disease and/or transmission. However, the measurement of vaccine efficacy is challenging, as efficacy trials need to include large cohorts with verum and placebo cohorts. In the future, this will be even more challenging as further vaccine candidates will receive approval, an increasing number of humans will receive vaccinations and incidence might decrease. To evaluate novel and second-generation vaccine candidates, randomized placebo-controlled trials might not be appropriate anymore. Correlates of protection (CoP) could be an important tool to evaluate novel vaccine candidates, but vaccine-induced CoP have not been clearly defined for SARS-CoV-2 vaccines. In this review, we report on immunogenicity against natural SARS-CoV-2 infection, vaccine-induced immune responses and discuss immunological markers that can be linked to protection. By discussing the immunogenicity and efficacy of forerunner vaccines, we aim to give a comprehensive overview of possible efficacy measures and CoP.

Longitudinal Development of Antibody Responses in COVID-19 Patients of Different Severity with ELISA, Peptide, and Glycan Arrays: An Immunological Case Series.

The current COVID-19 pandemic is caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). A better understanding of its immunogenicity can be important for the development of improved diagnostics, therapeutics, and vaccines. Here, we report the longitudinal analysis of three COVID-19 patients with moderate (#1) and mild disease (#2 and #3). Antibody serum responses were analyzed using spike glycoprotein enzyme linked immunosorbent assay (ELISA), full-proteome peptide, and glycan microarrays. ELISA immunoglobulin A, G, and M (IgA, IgG, and IgM) signals increased over time for individuals #1 and #2, whereas #3 only showed no clear positive IgG and IgM result. In contrast, peptide microarrays showed increasing IgA/G signal intensity and epitope spread only in the moderate patient #1 over time, whereas early but transient IgA and stable IgG responses were observed in the two mild cases #2 and #3. Glycan arrays showed an interaction of antibodies to fragments of high-mannose and core N-glycans, present on the viral shield. In contrast to protein ELISA, microarrays allow for a deeper understanding of IgA, IgG, and IgM antibody responses to specific epitopes of the whole proteome and glycans of SARS-CoV-2 in parallel. In the future, this may help to better understand and to monitor vaccination programs and monoclonal antibodies as therapeutics.

Ebola Virus Disease Survivors Show More Efficient Antibody Immunity than Vaccinees Despite Similar Levels of Circulating Immunoglobulins.

The last seven years have seen the greatest surge of Ebola virus disease (EVD) cases in equatorial Africa, including the 2013-2016 epidemic in West Africa and the recent epidemics in the Democratic Republic of Congo (DRC). The vaccine clinical trials that took place in West Africa and the DRC, as well as follow-up studies in collaboration with EVD survivor communities, have for the first time allowed researchers to compare immune memory induced by natural infection and vaccination. These comparisons may be relevant to evaluate the putative effectiveness of vaccines and candidate medical countermeasures such as convalescent plasma transfer. In this study, we compared the long-term functionality of anti-EBOV glycoprotein (GP) antibodies from EVD survivors with that from volunteers who received the recombinant vesicular stomatitis virus vectored vaccine (rVSV-ZEBOV) during the Phase I clinical trial in Hamburg. Our study highlights important differences between EBOV vaccination and natural infection and provides a framework for comparison with other vaccine candidates.

Prospective observational study on the pharmacokinetic properties of the Irrua ribavirin regimen used in routine clinical practice in patients with Lassa fever in Nigeria.

INTRODUCTION: Lassa fever (LF) is a severe and often fatal systemic disease in humans and affects a large number of countries in West Africa. Treatment options are limited to supportive care and the broad-spectrum antiviral agent ribavirin. However, evidence for ribavirin efficacy in patients with LF is poor and pharmacokinetic (PK) data are not available.Irrua Specialist Teaching Hospital (ISTH) developed an intravenous ribavirin regimen different to the WHO recommendation. Apart from a lower total daily dose the drug is usually administered once per day which reduces the exposure of personnel to patients with LF. The aim of this study is to characterise the PK of the Irrua ribavirin regimen. METHODS AND ANALYSIS: This prospective, observational clinical study will assess PK properties of the Irrua ribavirin regimen on routinely ribavirin-treated patients with LF at ISTH, a referral hospital serving 19 local governmental areas in a LF endemic zone in Nigeria. Participants will be adults with PCR-confirmed LF. The primary objective is to describe classical PK parameters for ribavirin (maximum plasma drug concentration, time to maximum plasma drug concentration, area under the plasma drug concentration vs time curve, half-life time T1/2, volume of distribution). Blood samples will be collected at 0.5, 1, 3, 5, 8, 12 and 24 hours after doses on day 1, day 4 and day 10 of ribavirin treatment. Ribavirin plasma concentrations will be determined using liquid chromatography coupled to tandem mass spectrometry. ETHICS AND DISSEMINATION: The study will be conducted in compliance with the protocol, the Declaration of Helsinki, Good Clinical Practice (GCP) and the Nigerian National Code for Health Research Ethics. The protocol has received approval by the Health Research Ethics Committee of ISTH. Results will be made available to LF survivors, their caregivers, the funders, LF research society and other researchers. REGISTRATION DETAILS: ISRCTN11104750.

Safety and immunogenicity of a modified vaccinia virus Ankara vector vaccine candidate for Middle East respiratory syndrome: an open-label, phase 1 trial.

BACKGROUND: The Middle East respiratory syndrome coronavirus (MERS-CoV) causes a respiratory disease with a case fatality rate of up to 35%. Given its potential to cause a public health emergency and the absence of efficacious drugs or vaccines, MERS is one of the WHO priority diseases warranting urgent research and development of countermeasures. We aimed to assess safety and tolerability of an anti-MERS-CoV modified vaccinia virus Ankara (MVA)-based vaccine candidate that expresses the MERS-CoV spike glycoprotein, MVA-MERS-S, in healthy adults. METHODS: This open-label, phase 1 trial was done at the University Medical Center Hamburg-Eppendorf (Hamburg, Germany). Participants were healthy men and women aged 18-55 years with no clinically significant health problems as determined during medical history and physical examination, a body-mass index of 18·5-30·0 kg/m2 and weight of more than 50 kg at screening, and a negative pregnancy test for women. A key exclusion criterion was a previous MVA vaccination. For the prime immunisation, participants received doses of 1 × 107 plaque-forming unit (PFU; low-dose group) or 1 × 108 PFU (high-dose group) MVA-MERS-S intramuscularly. A second identical dose was administered intramuscularly as a booster immunisation 28 days after first injection. As a control group for immunogenicity analyses, blood samples were drawn at identical study timepoints from six healthy adults, who did not receive any injections. The primary objectives of the study were safety and tolerability of the two dosage levels and reactogenicity after administration. Immunogenicity was assessed as a secondary endpoint by ELISA and neutralisation tests. T-cell immunity was evaluated by interferon-γ-linked enzyme-linked immune absorbent spot assay. All participants who were vaccinated at least once were included in the safety analysis. Immunogenicity was analysed in the participants who completed 6 months of follow-up. This trial is registered with ClinicalTrials.gov, NCT03615911, and EudraCT, 2014-003195-23 FINDINGS: From Dec 17, 2017, to June 5, 2018, 26 participants (14 in the low-dose group and 12 in the high-dose group) were enrolled and received the first dose of the vaccine according to their group allocation. Of these, 23 participants (12 in the low-dose group and 11 in the high-dose group) received a second dose of MVA-MERS-S according to their group allocation after a 28-day interval and completed follow-up. Homologous prime-boost immunisation with MVA-MERS-S revealed a benign safety profile with only transient mild-to-moderate reactogenicity. Participants had no severe or serious adverse events. 67 vaccine-related adverse events were reported in ten (71%) of 14 participants in the low-dose group, and 111 were reported in ten (83%) of 12 participants in the high-dose group. Solicited local reactions were the most common adverse events: pain was observed in 17 (65%; seven in the low-dose group vs ten in the high-dose group) participants, swelling in ten (38%; two vs eight) participants, and induration in ten (38%; one vs nine) participants. Headaches (observed in seven participants in the low-dose group vs nine in the high-dose group) and fatigue or malaise (ten vs seven participants) were the most common solicited systemic adverse events. All adverse events resolved swiftly (within 1-3 days) and without sequelae. Following booster immunisation, nine (75%) of 12 participants in the low-dose group and 11 (100%) participants in the high-dose group showed seroconversion using a MERS-CoV S1 ELISA at any timepoint during the study. Binding antibody titres correlated with MERS-CoV-specific neutralising antibodies (Spearman's correlation r=0·86 [95% CI 0·6960-0·9427], p=0·0001). MERS-CoV spike-specific T-cell responses were detected in ten (83%) of 12 immunised participants in the low-dose group and ten (91%) of 11 immunised participants in the high-dose group. INTERPRETATION: Vaccination with MVA-MERS-S had a favourable safety profile without serious or severe adverse events. Homologous prime-boost immunisation induced humoral and cell-mediated responses against MERS-CoV. A dose-effect relationship was demonstrated for reactogenicity, but not for vaccine-induced immune responses. The data presented here support further clinical testing of MVA-MERS-S in larger cohorts to advance MERS vaccine development. FUNDING: German Center for Infection Research.