Lower Respiratory Tract Infection (LRTI)

The goal of this clinical trial is to assess if BUCCALIN® works In the Prophylaxis of Recurrent Lower Respiratory Tract Infections (RLRTIS). It will also evaluate the safety of BUCCALIN®. The primary aim is to reduce the number of infection episodes in the treatment period (12 months) in the BUCCALIN® group versus the Placebo group. Patients diagnosed with RLRTIS will be screened for enrolment. Patients will be requested to provide informed consent before the start of the study related assessments. Eligible patients who meet the study inclusion and exclusion criteria will be randomized with a 1:1 ratio allocation to the 2 treatment groups. Researchers will compare BUCCALIN® (gastro-resistant tablets) to a placebo (gastro-resistant tablets containing only excipients) to treat RLRTIS. Patients who participate in the study will perform several study visits divided as reported below: * Run-in phase (12 months): patients will not receive any treatment. This phase is designed to increase adherence to the study and reduce loss to follow-up in the clinical trial. During this phase, patients should experience ≥ 2 episodes of RTIs to be eligible for the Treatment period. * Treatment period (12 months): patients will receive BUCCALIN® or Placebo treatment for 12 consecutive months (3 days per month, posology as per authorized SmPC). * Follow-up period (12 months): patients will not receive any treatment. This phase is designed to observe how patients respond to treatments.

The goal of this observational study is to learn about the causes, severity, and long-term effects of respiratory tract infections (RTIs) in young children from birth to five years of age in Colombia and Panamá. The main questions it aims to answer are: How often do respiratory infections occur in children under two years old, and which viruses or bacteria cause them? Why do some children develop more severe infections than others? Do early infections or vaccinations change how the immune system responds to future illnesses? How do viruses and bacteria interact in the respiratory tract to influence disease severity and long-term respiratory health? Researchers will follow newborns from birth until age five to understand how respiratory infections develop and affect children's health over time. Participants will not receive any experimental treatment. Families who join the study will: Be contacted twice a week through a phone app or phone calls to check for symptoms of respiratory infection. Attend in-person visits if their child becomes ill and every six months for routine follow-up. Provide nasal and blood samples during illness episodes so researchers can identify the viruses or bacteria causing infection and study how the immune system responds. This study began in May 2024 and is being conducted in Cali, Colombia, and Panamá City, Panamá. The research team plans to continue to include participants and continue active follow-up until the children reach five years of age. The information collected will help scientists and health professionals understand how different pathogens cause respiratory infections, what factors increase the risk of severe illness, and how early infections may influence long-term lung health. The study's findings will support future efforts to prevent and treat respiratory diseases in young children.

Antibiotic resistance is driven by overuse, especially for viral respiratory infections. Procalcitonin (PCT), a biomarker for bacterial infections, helps guide antibiotic therapy more precisely, reducing unnecessary use and improving outcomes. Studies, including large trials and economic models across several countries, show PCT-guided treatment lowers mortality, antibiotic exposure, therapy duration and related complications, potentially reducing hospital costs despite initial testing expenses.