This clinical trial is focused on studying the effectiveness of different types of vaccines for preventing Influenza, commonly known as the flu. The study will compare two types of vaccines: a nasal spray vaccine called FluMist and an injectable vaccine known as Vaxigriptetra. The nasal spray vaccine contains live but weakened strains of the flu virus, while the injectable vaccine contains purified antigens, which are parts of the virus that help the body recognize and fight the flu.
The purpose of the study is to understand how these vaccines help the body build immunity, particularly in the airways, which are the passages that carry air to the lungs. Participants in the study will receive either the nasal spray or the injectable vaccine, and some may receive a placebo, which looks like the real vaccine but does not contain any active ingredients. The study will monitor participants over a period of time to see how their immune systems respond to the vaccines.
Throughout the study, researchers will collect samples to measure the body’s immune response. This includes looking at specific cells and antibodies, which are proteins that help fight infections. The study aims to provide insights into how well each vaccine works in establishing immunity against different strains of the flu virus. This information could help improve flu prevention strategies in the future.



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