NCT07445763

TARSILA Real-World Evidence Study

Real-world Effectiveness of maTernAl RSVpreF vaccInation Against RSV-associated Acute Respiratory ilLness in Infants in BrAzil (TARSILA Study): a Multicentre, Prospective, Test-negative, Case-Control Study

• Status: Not Yet Recruiting
• Phase: —
• Study type: Observational
• Enrollment: 5,000 (estimated)
• Sponsor: Inova Medical · Academic / Other
• Sex: All
• Age: 0 Days – 360 Days
• Healthy volunteers: Not accepted

Summary

The overall objective of Tarsila Study is to estimate the real-world vaccine effectiveness of maternal RSVpreF immunization during pregnancy in Brazil against medically attended (inpatient and outpatient) respiratory syncytial virus-associated acute respiratory illness in infants. To achieve this, two multicenter, prospective, test-negative case-control studies will be conducted among infants with ARI: the TARSILA Inpatient Study, evaluating hospitalized infants and the TARSILA Outpatient Study, evaluating infants managed in outpatient settings.

Detailed description

Tarsila comprises two multicenter, prospective, case-control studies using a test-negative design in Southern Brazil (states of Rio Grande do Sul, Santa Catarina, and Paraná). The Tarsila Inpatient study will enroll infants hospitalized due to acute respiratory illness and will be conducted at referral hospitals. The Tarsila Outpatient study will enroll infants with acute respiratory illness managed in outpatient settings and will be conducted at outpatient healthcare facilities. Both studies are aligned with the nationwide introduction of maternal RSVpreF vaccination in December 2025, with enrollment occurring from April, 2026 to September, 2028. In both studies, the same clinical case definition will be applied to cases and controls. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) for RSV will be prospectively performed to classify case infants (RT-qPCR positive for RSV) and control infants (RT-qPCR negative for RSV). Maternal RSVpreF vaccination status and potential confounders will be assessed through structured interviews and review of medical records.

Conditions

• Respiratory Syncytial Virus (RSV)
• Maternal Immunization
• Acute Respiratory Illness (ARI)
• Lower Respiratory Tract Disease
• Infant Outcomes

Interventions

Type	Name	Description
BIOLOGICAL	respiratory syncytial virus bivalent prefusion F vaccine	For both studies, the primary exposure is maternal receipt of respiratory syncytial virus bivalent prefusion F vaccination during pregnancy in accordance with the Brazilian National Immunization Program recommendation (24⁺⁰/₇ to 36⁺⁶/₇ weeks' gestation) with the receipt of the vaccine 14 days or more before delivery.

Timeline

• Start date: 2026-04-30
• Primary completion: 2028-09-30
• Completion: 2028-12-31
• First posted: 2026-03-03
• Last updated: 2026-03-03

Regulatory

• FDA-regulated drug study