Influenza is a contagious respiratory illness that can cause fever, cough, muscle aches, and sometimes serious complications. This study evaluates a new vaccine that mixes an inactivated flu vaccine called GC IIV with a protein‑based component known as OVX836, and compares it with the individual components, a standard flu vaccine named Vaxigrip, and a placebo (a simple saline solution). All injections are given by intramuscular route, meaning the medicine is placed into the muscle using a short needle.
The main aim of the trial is to assess the safety and immune response of the mixed vaccine. Participants receive a single injection and are observed for a short period right after the shot. They then return for follow‑up visits a few weeks later and again several months later to check for any side effects and to see how well the body has responded to the vaccine.
During the study, volunteers are asked to report any local reactions such as soreness at the injection site and systemic symptoms like fever or fatigue. Small blood samples are taken to measure the level of antibodies—proteins that help the immune system recognize and fight the flu virus—and to evaluate other immune cells. Any serious problems that arise are recorded and reviewed throughout the study period.
Belgium 
