Background: At the beginning of the 2018-2020 outbreak of Ebola virus disease (EVD) in eastern Democratic Republic of Congo (DRC), no vaccine had been licensed. However, cluster-randomized evidence from Guinea in 2015 had indicated that ring vaccination around new cases (targeting contacts and contacts-of-contacts) with the use of single-dose live-replicating rVSV-ZEBOV-GP vaccine reduced EVD rates starting 10 days after vaccination. Thus, ring vaccination was added to the standard control measures for that outbreak.
View Article and Find Full Text PDFBMC Med
November 2024
Transmission trees can be established through detailed contact histories, statistical or phylogenetic inference, or a combination of methods. Each approach has its limitations, and the extent to which they succeed in revealing a 'true' transmission history remains unclear. In this study, we compared the transmission trees obtained through contact tracing investigations and various inference methods to identify the contribution and value of each approach.
View Article and Find Full Text PDFBackground: The 2013-16 Ebola virus disease epidemic in west Africa caused international alarm due to its rapid and extensive spread resulting in a significant death toll and social unrest within the affected region. The large number of cases provided an opportunity to study the long-term kinetics of Zaire ebolavirus-specific immune response of survivors in addition to known contacts of those infected with the virus.
Methods: In this observational cohort study, we worked with leaders of Ebola virus disease survivor associations in two regions of Guinea, Guéckédou and Coyah, to recruit survivors of Ebola virus disease, contacts from households of individuals known to have had Ebola virus disease, and individuals who were not knowingly associated with infected individuals or had not had Ebola virus disease symptoms to serve as negative controls.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the aetiological agent of coronavirus disease 2019 (COVID-19), an emerging respiratory infection caused by the introduction of a novel coronavirus into humans late in 2019 (first detected in Hubei province, China). As of 18 September 2020, SARS-CoV-2 has spread to 215 countries, has infected more than 30 million people and has caused more than 950,000 deaths. As humans do not have pre-existing immunity to SARS-CoV-2, there is an urgent need to develop therapeutic agents and vaccines to mitigate the current pandemic and to prevent the re-emergence of COVID-19.
View Article and Find Full Text PDFCOVID-19 represents a global crisis. Rapidly conducting a clinical trial with the rigor necessary to obtain reliable results requires the collaboration of various participants involved in the development, evaluation and authorization of clinical trials (CT) such as the trial sponsor, researchers, regulatory authority and the ethics committee (EC). Carrying out these studies is not only scientifically appropriate, but an ethical and moral obligation to guarantee our patients effective treatment.
View Article and Find Full Text PDFThe 2014-2015 outbreak of Ebola Virus Disease (EVD) in West Africa was unprecedented in size and scope. The World Health Organization, government of Guinea and other partners undertook a field trial of efficacy of an Ebola vaccine in Guinea, with a parallel immunogenicity study in front-line workers. However, several obstacles had to be overcome.
View Article and Find Full Text PDFBackground: In October 2015, 65 people came into direct contact with a healthcare worker presenting with a late reactivation of Ebola virus disease (EVD) in the United Kingdom. Vaccination was offered to 45 individuals with an initial assessment of high exposure risk.
Methods: Approval for rapid expanded access to the recombinant vesicular stomatitis virus-Zaire Ebola virus (rVSV-ZEBOV) vaccine as an unlicensed emergency medicine was obtained from the relevant authorities.
Public health emergencies, such as an Ebola disease outbreak, provide a complex and challenging environment for the evaluation of candidate vaccines. Here, we outline the need for flexible and responsive vaccine trial designs to be used in public health emergencies, and we summarize recommendations for their use in this setting.
View Article and Find Full Text PDFBackground: Licensed vaccines are urgently needed for emerging infectious diseases, but the nature of these epidemics causes challenges for the design of phase III trials to evaluate vaccine efficacy. Designing and executing rigorous, fast, and ethical, vaccine efficacy trials is difficult, and the decisions and limitations in the design of these trials encompass epidemiological, logistical, regulatory, statistical, and ethical dimensions.
Results: Trial design decisions are complex and interrelated, but current guidance documents do not lend themselves to efficient decision-making.
Understanding risk factors for Ebola transmission is key for effective prediction and design of interventions. We used data on 860 cases in 129 chains of transmission from the latter half of the 2013-2016 Ebola epidemic in Guinea. Using negative binomial regression, we determined characteristics associated with the number of secondary cases resulting from each infected individual.
View Article and Find Full Text PDFWe sought datasets with granular age distributions of rotavirus-positive disease presentations among children <5 years of age, before the introduction of rotavirus vaccines. We identified 117 datasets and fit parametric age distributions to each country dataset and mortality stratum. We calculated the median age and the cumulative proportion of rotavirus gastroenteritis events expected to occur at ages between birth and 5.
View Article and Find Full Text PDFLancet Infect Dis
December 2017
Background: In March, 2016, a flare-up of Ebola virus disease was reported in Guinea, and in response ring vaccination with the unlicensed rVSV-ZEBOV vaccine was introduced under expanded access, the first time that an Ebola vaccine has been used in an outbreak setting outside a clinical trial. Here we describe the safety of rVSV-ZEBOV candidate vaccine and operational feasibility of ring vaccination as a reactive strategy in a resource-limited rural setting.
Methods: Approval for expanded access and compassionate use was rapidly sought and obtained from relevant authorities.
Simpler schedules for human papillomavirus (HPV) vaccine delivery could improve vaccine coverage and the effectiveness of cervical cancer prevention. The objective of this study was to systematically review evidence about the effects of two-dose compared with three-dose schedules for human papillomavirus (HPV) vaccine and to describe the uptake of two-dose HPV vaccination schedules globally. We searched PubMed, the Cochrane Central Registry of Controlled Trials, trials registers, and manufacturers' databases from their earliest date to February 2016.
View Article and Find Full Text PDFBackground: 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.
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.
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