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NCT07279298

Effectiveness of Immunization in Preventing Severe Acute Respiratory Infection RSV

Sponsor: Bogotá District Health Secretariat

View on ClinicalTrials.gov

Summary

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.

Official title: Effectiveness of Immunization in Preventing Severe Acute Respiratory Infection Associated With Respiratory Syncytial Virus-RSV- in Infants Under 6 Months of Age in Bogotá: a Case-control Study With a Negative Test Design

Key Details

Gender

All

Age Range

1 Day - 180 Days

Study Type

OBSERVATIONAL

Enrollment

1097

Start Date

2026-02-01

Completion Date

2027-07-31

Last Updated

2025-12-12

Healthy Volunteers

Conditions

Respiratory Syncytial Virus Infections Severe Acute Respiratory Infection Bronchiolitis, Viral Viral Respiratory Tract Infection

Interventions

BIOLOGICAL

RSVpreF vaccine (Abrysvo) and Nirsevimab (Beyfortus) or unexposed

Maternal vaccination administered between 28 and 36 weeks of gestation and Single-dose monoclonal antibody administered to newborns whose mothers did not receive effective RSVpreF vaccination or unexposed

Inclusion Criteria: * Age: Infants younger than 6 months at the time of hospital admission. * Residence: Maternal residence in Bogotá, Colombia, verified through clinical record, identification document, or health system registry. * Clinical Condition: Hospitalization due to severe acute respiratory infection (SARI) meeting the district operational definition (presence of fever, cough, and/or signs of respiratory distress, requiring inpatient management). * Laboratory Testing: Respiratory specimen collected and tested for RSV by RT-PCR or validated antigen test within ≤48 hours of hospital admission, or repeated within 24-48 hours if initial test is negative. * Exposure Eligibility Window: Infant born ≥5 weeks after the start of the RSVpreF maternal vaccination campaign in Bogotá, ensuring opportunity for maternal immunization. Exclusion Criteria: * Prematurity: Infants born at ≤32 weeks of gestation. * Healthcare-associated respiratory infection: Symptom onset \>48 hours after hospital admission for another condition. * Non-respiratory hospital admission: Primary reason for hospitalization unrelated to respiratory disease (e.g., trauma, elective surgery). * Vaccination status unverifiable: Inability to confirm maternal RSVpreF vaccination status after reasonable attempts to verify through registry, vaccination card, or prenatal documentation. * Duplicate episodes: Readmission for the same respiratory episode ≤14 days after discharge (only the first episode will be included). * Delayed sampling: First respiratory sample obtained \>48-72 hours after initial admission to the health system. * Lethal congenital conditions: Congenital or genetic disorders incompatible with life or that substantially alter the expected clinical course. * Concurrent interventional study participation: Enrollment in another clinical trial that may affect respiratory outcomes. * Inability to establish mother-infant linkage due to adoption, loss of parental custody, or absence of biological maternal records.