Ongoing Clinical Trials for Yellow Fever
There are currently 3 clinical trials investigating different approaches to yellow fever prevention and treatment. These studies are taking place across Europe, comparing vaccine delivery methods, testing new vaccines, and exploring antiviral medications to prevent infection. Yellow fever is a viral infection transmitted by mosquitoes that can cause serious illness affecting the liver and kidneys.
Clinical trial locations
- Belgium
- Espagne
- Finland
- France
- Germany
- Netherlands
- Spain
Study Comparing Different Injection Methods of Yellow Fever Vaccine in Adults
This trial is examining whether different methods of administering the yellow fever vaccine affect how well it protects against infection. Researchers are comparing three injection techniques: intradermal (into the skin), subcutaneous (under the skin), and intramuscular (into the muscle). The study uses STAMARIL®, which contains a live, weakened form of the yellow fever virus.
Who can participate: The study is looking for healthy adults between 18 and 50 years old with a Body Mass Index (BMI) between 18.5 and 30. Participants must be willing to avoid donating blood and receiving other vaccinations for 30 days after the study vaccination. Women who can become pregnant must agree to use effective contraception for up to 30 days after vaccination.
Who cannot participate: People who have had severe allergic reactions to previous yellow fever vaccines cannot join. The study also excludes individuals with weakened immune systems, pregnant or breastfeeding women, anyone with thymus problems, those currently experiencing fever or active infection, people who received another live vaccine within the last 4 weeks, and individuals allergic to eggs or any vaccine component.
Study focus: The main goal is to understand which injection method produces the strongest immune response, particularly looking at memory T cells in the skin that help protect against future infections. Participants will be monitored for up to 120 days after vaccination, with follow-up visits on days 0, 14, 28, and 120. Blood samples will be collected to measure immune response, and any side effects will be carefully tracked.
Investigational approach: The Yellow Fever Vaccine being studied is a live attenuated vaccine, meaning it contains a weakened form of the virus that cannot cause disease in healthy individuals but can stimulate immune protection.
Study Comparing the Safety and Immune Response of the Investigational vYF Vaccine and Stamaril for Yellow Fever in Adults in Europe and Asia
This international trial is comparing a new investigational vaccine called vYF with the established Stamaril vaccine. Both vaccines are designed to help the body build immunity against the yellow fever virus by stimulating antibody production.
Who can participate: Adults between 18 and 60 years old who can attend all scheduled visits are eligible. Women who can become pregnant must have negative pregnancy tests before vaccination and again on Day 29, and must agree to use effective birth control from at least 4 weeks before vaccination until at least 4 weeks after (12 weeks for participants in France). Participants under 21 years old in Singapore need parental consent. Those in the Asian countries additional group must have at least one biological parent of Chinese origin.
Who cannot participate: The study excludes people who have previously been vaccinated against yellow fever, those with known allergies to vaccine components, individuals with weakened immune systems, pregnant or breastfeeding women, anyone with a history of severe vaccine reactions, people currently participating in another clinical trial, and those with serious illnesses requiring ongoing medical treatment.
Study focus: Researchers will compare how effectively the vYF vaccine generates an immune response compared to Stamaril by measuring antibody levels in the blood. Participants will receive a single injection under the skin and be observed for immediate reactions. Follow-up visits occur at 28 days, 6 months, 1 year, and annually up to 5 years to monitor long-term immune response and safety.
Investigational drugs: The vYF candidate vaccine stimulates the immune system to recognize and fight the yellow fever virus. Stamaril® serves as the control vaccine, providing a benchmark to evaluate whether the new vYF vaccine is equally effective in preventing infection.
Study on Sofosbuvir for Preventing Yellow Fever in Healthy Volunteers
This innovative trial is exploring a completely different approach to protection by testing whether sofosbuvir, an antiviral medication normally used to treat hepatitis C, can prevent the yellow fever virus from multiplying in the body. The study uses Sovaldi 400 mg film-coated tablets containing sofosbuvir.
Who can participate: Healthy men and women between 18 and 50 years old without significant health issues are eligible. People with stable long-term health conditions that haven’t required treatment changes or hospitalization in the last six weeks might still qualify, with the study doctor making the final decision.
Who cannot participate: The study is specifically for healthy volunteers, so people with ongoing medical conditions are generally excluded. Vulnerable populations who need special protection, such as children or those unable to make decisions for themselves, cannot participate.
Study focus: The research aims to determine whether sofosbuvir can block the replication of the YF17D virus strain in the body. Participants will be monitored through regular blood and urine tests to check for virus presence and antibody development. The study will also carefully track safety by monitoring liver function tests and blood counts. Regular follow-up visits allow the healthcare team to assess medication effects and any side effects participants may experience.
Investigational drug: Sofosbuvir is an RNA polymerase inhibitor that works by blocking a specific enzyme the virus needs to multiply. While proven effective against hepatitis C, this trial investigates whether it can also protect against yellow fever, particularly for people who may be exposed to the virus in high-risk situations where vaccination isn’t practical or possible.
Summary
The three ongoing trials represent diverse strategies for addressing yellow fever prevention. Two studies focus on vaccination approaches—one optimizing delivery methods for the existing STAMARIL® vaccine in Belgium, and another comparing a new vYF vaccine against the established Stamaril vaccine across multiple European countries including Germany, Spain, Finland, and France. The third trial in the Netherlands takes an innovative approach by testing an antiviral medication typically used for hepatitis C to see if it can prevent viral replication.
A notable concentration of vaccine research is occurring across Western Europe, reflecting the region’s role in developing and testing preventive measures for travelers to endemic areas. The studies target different age groups, with the Belgian and Dutch trials focusing on younger adults (18-50 years) while the multinational vaccine comparison accepts participants up to age 60. All three trials emphasize careful safety monitoring and long-term follow-up to assess both immediate and sustained protection against this serious mosquito-borne viral infection.
