Effectiveness of Immunization in Preventing Severe Acute Respiratory Infection RSV in Children Under 6 Months in Bogotá

This study aims to evaluate the real-world effectiveness of two preventive immunization strategies against Respiratory Syncytial Virus (RSV)-associated severe acute respiratory infection in infants less than six months of age in Bogotá, Colombia. The strategies include maternal vaccination with RSVpreF administered between 28 and 36 weeks of gestation and neonatal immunization with nirsevimab for infants born to mothers who did not receive RSVpreF during pregnancy. Using a test-negative case-control design embedded in the city's sentinel surveillance system, infants hospitalized for severe respiratory infection will be systematically tested for RSV. Comparative vaccine effectiveness will be estimated to determine the impact of maternal RSV vaccination and neonatal monoclonal antibody immunization on RSV-associated hospitalizations, intensive care admissions, and mortality. The study will generate real-world evidence to inform local and regional public health decisions and guide the implementation of cost-effective hybrid immunization strategies against RSV in middle-income settings.

NCT Number	NCT07279298
Lead Sponsor	Bogotá District Health Secretariat
Conditions	Respiratory Syncytial Virus Infections, Severe Acute Respiratory Infection, Bronchiolitis, Viral, Viral Respiratory Tract Infection
Enrollment	1,097 participants
Start Date	2026-01-01
Primary Completion	2026-12-31 (estimated)
Study Completion	2027-07-31 (estimated)
Updated on ClinicalTrials.gov	2026-08-06