Dengue Fever

Dengue fever is caused by an infection with the dengue virus. Vaccination with Dengue Tetravalent Vaccine (TDV) can help prevent dengue fever. The purpose of this study is to collect information of vaccination with TDV when given to children younger than 2 years. The main aims of this study are to learn how safe the vaccine is and how well it works to activate a young child's immune system (this is called immunogenicity). Children between the age of 6 and 21 months will receive two vaccinations with either TDV or placebo 3 months apart. Blood samples will be taken before and after the vaccination as well as throughout the study. These are necessary to check how well the vaccine works to activate the immune system. During the study, participants will visit their study clinic 8 times for vaccinations, blood draws and health checks.

Dengue fever is caused by an infection with the dengue virus. Vaccination with Dengue Tetravalent Vaccine (TDV) can help prevent dengue fever. Researchers have seen that dengue fever now also happens more often in elderly persons. The main aim of this study is to learn more about the side effects of TDV in adult (45 - 60 years) and elderly (60 - 79 years) persons and about TDV's ability to create an immune response in adult and elderly persons. Another aim is to learn about the side effects of TDV in adult and elderly persons in endemic countries who have one or more additional medical conditions (called comorbidities) such as diabetes mellitus, hypertension or a chronic kidney condition. In this study, participants will receive 2 vaccinations with TDV (the second 3 months after the first). During the study, participants will visit their study clinic 5 times.

The main aim of this study is to collect more information on the effectiveness of TDV when used in a pilot public vaccination program for children and adolescents participating in a community-based cohort in Southeast Asian countries with high dengue transmission, specifically Thailand, Indonesia, and Malaysia where TDV is already approved for use. The study will include cohort participants (individual follow-up of 3 years) who may or may not later be vaccinated with TDV as part of a pilot public vaccination program in the study countries. The study will investigate if cohort participants who were vaccinated with TDV have less hospital stays due to dengue than cohort participants who were not vaccinated with TDV. The study will also provide further information on the effectiveness of TDV against the least common dengue virus serotypes (DENV-3 and DENV-4).

Dengue fever, a viral infection transmitted by Aedes mosquitoes, is a major health issue in tropical and subtropical regions. Around 20-30% of symptomatic patients developed Dengue Hemorrhagic Fever (DHF), which leads to impaired hemostasis, subsequently increasing the risk of bleeding. The hemostatic abnormalities associated with dengue infection included vascular permeability, platelet dysfunction, and coagulation defects. Therefore, Individuals with underlying bleeding disorders are at increased risk of bleeding. Dengue infection in patients with hemophilia was reported, including six of 843 patients in the cohort with underlying hemophilia: five with hemophilia A and one with hemophilia B. Replacement therapy was more commonly used in patients with bleeding disorders and dengue than in patients with other febrile illnesses. All of them had bleeding during dengue infection. The mortality rate was high at 16%. Despite the importance of this issue, there is a lack of registries or data-collection systems to determine the bleeding complications, the requirement for replacement therapy, and the outcome of dengue infection in congenital bleeding disorders (CBDs). Therefore, this research aims to establish a registry of dengue infections among individuals with CBDs. The study is a multicenter, retrospective study from 1 January 2015 to 31 December 2025 and a prospective cohort study involving hospitals that treat individuals with CBDs and dengue. The registry format will be provided using REDCap system.

This 3-year prospective observational study aims to identify clinical and laboratory risk factors associated with hospitalization in patients with confirmed dengue virus infection. It also seeks to analyze real-world transfusion practices and their outcomes. The study will be conducted in a second-level hospital in northern Mexico and will follow patients from emergency department entry to clinical resolution or hospital discharge.

The goal of this clinical trial is to understand if Resomelagon can treat adult patients with Dengue virus infection. The main questions the investigators aim to answer are: Is Resomelagon safe to use in patients with Dengue? Is Resomelagon able to reduce the duration of illness? (defined by clinical and laboratory criteria) Participants will be allocated to Resomelagon or placebo groups in this study and asked to take the medication and submitted to blood tests.

Exanthematous fevers are a global public health problem. The spread of arboviruses due to various factors, including climate change, has resulted in major epidemics such as the one that occurred in Brazil in 2024, representing an extremely concerning scenario from both epidemiological and healthcare perspectives. In addition to this, the reemergence of childhood exanthematous diseases in several countries, including Brazil, is alarming and occurs due to declining vaccination coverage and increased migratory movements. These diseases present overlapping clinical symptoms, and their differential diagnosis is often challenging, which, in a context of dengue and Chikungunya epidemics like the current one, may lead to underreporting of diseases such as measles and rubella. This project aims to build a prospective registry of the occurrence of dengue, Chikungunya, measles, and rubella in various healthcare centers in Brazil, in order to better understand the epidemiological scenario, identify clinical variables associated with different diagnoses, and describe healthcare bottlenecks that may hinder proper reporting and identification of these diseases.

ZAP-DENGUE is a pilot randomized, double-blind, placebo-controlled evaluation of the safety and efficacy of five days of intravenous zanamivir treatment to treat vascular permeability syndrome which is the main cause of death in dengue fever.