In-depth Analysis of the Immune Responses in the Upper Respiratory Tract of Influenza-infected Children

What this Trial Is About

Researchers are studying the immune response in the upper respiratory tract of children aged 2 to 5 who have a laboratory-confirmed influenza infection. This observational study aims to measure inflammation in the nasal cavity, relate it to viral load and clinical symptoms, and compare it with responses in the blood. The project also includes comparison to children without infection or those vaccinated with a nasal flu vaccine in a related study. Participants will have two main study visits: the first within 72 hours of hospital admission and the second about one month later. During these visits, samples of blood, nasal lining fluid, nasal cells, and saliva will be collected. Nasal lining fluid and saliva samples will also be taken every two to three days until symptoms resolve. Symptom-related questions will be asked during these visits. Throughout the study, researchers will assess inflammatory markers like pro-inflammatory cytokines in nasal fluid, immune cell types in nasal and blood samples, influenza-specific antibodies, and viral load in nasal and saliva samples. Clinical symptoms and outcomes such as fever duration, oxygen use, secondary infections, intensive care stays, and rehospitalization will be recorded. The total study participation lasts about one month from initial hospitalization.

In-depth Analysis of the Immune Responses in the Upper Respiratory Tract of Influenza-infected Children