Population
542 babies born at ≤29+6 weeks’ gestation, recruited before discharge by UK neonatal units.
Demonstration redesign — scientific details derived from the published BALLOON protocol
Preterm Lung Health Research
A clinical trial for babies born very prematurelyAbout the research
Finding better ways to protect developing lungs
BALLOON is a UK randomised clinical trial asking whether Bactek can reduce lower respiratory tract infections in babies born very or extremely prematurely.
Why is the trial needed?
Respiratory infections may compound vulnerability after very preterm birth.
Babies born at or before 29 weeks and 6 days have lungs and immune systems that are still developing. Pre-existing respiratory vulnerability can be exacerbated by viral lower respiratory tract infections after discharge, leading to greater healthcare use than among babies born at term.
Protection against respiratory syncytial virus has advanced, but broader options for preventing infections caused by multiple respiratory viruses remain limited. Bactek—also known as MV130—is intended to stimulate trained immune responses. Its effectiveness in babies born very prematurely is not established; BALLOON is designed to test it rigorously.
Trial design
A fair comparison designed to minimise bias
Allocation
Participants are randomly assigned to Bactek or matching placebo in a parallel-group, double-blind design.
Treatment
Two 0.1 mL sublingual sprays once daily, starting at 37–43 weeks’ postmenstrual age or discharge if earlier.
Follow-up
Treatment and outcome collection continue until one year corrected age.
542 babiesenrolled before discharge
→Random allocationcomputer-generated
→Bactek or placebodaily sublingual spray
→One year corrected ageprimary follow-up point
What will BALLOON measure?
Outcomes that matter clinically and to families
The trial combines healthcare-confirmed events with symptoms, medication use, growth, safety, virology and family impact.
Primary outcome
Health-professional-diagnosed lower respiratory tract infections, captured through unscheduled GP visits, emergency-department attendances and hospital admissions between enrolment and one year corrected age.
Healthcare use
Number of parent-reported, health-professional-confirmed unscheduled visits and time to the first such visit for a lower respiratory tract infection.
Respiratory symptoms
Parent-reported wheeze episodes, aided by WheezeScan, and use of respiratory medications.
Growth and family impact
Weight, length and head circumference, together with parent or guardian time away from work and infant time away from nursery.
Safety and virology
Adverse reactions are assessed, and viruses associated with lower respiratory tract infections are identified.
Trial progress
113 babies have joined BALLOON
Recruitment began in March 2025 across UK neonatal units. Each participating family contributes to a robust answer about this potential preventive treatment.
View the recruitment dashboard →20.8%of the 542-participant target
Governance and oversight
Independent review and regulatory approvals
BALLOON is conducted within UK clinical-trial, ethical and regulatory frameworks.
Meets monthly and oversees day-to-day delivery.
Provides independent supervision of trial progress and conduct.
Reviews accumulating safety and trial information independently.
Wales Research Ethics Committee 3: 24/WA/0181.
MHRA clinical-trial authorisation: 21323/0063/001-0004.
ISRCTN14019493.
Families as research partners
Patient and public involvement
Parent and public contributors help ensure that the study question, participation burden, information and dissemination remain relevant to families. The final website should describe their specific contributions and how their feedback changed the study.
A national collaboration
Clinical, immunological and trial-methodology expertise
BALLOON is led by Professor Sailesh Kotecha at Cardiff University and coordinated by the Centre for Trials Research. Co-applicants and collaborators include colleagues from Cardiff, Newcastle, Leicester and Queen Mary University of London, working with neonatal teams across the UK.
Cardiff UniversityCentre for Trials ResearchNewcastle upon TyneUniversity Hospitals of LeicesterQueen Mary University of LondonUK neonatal units
Funding
NIHR Efficacy and Mechanism Evaluation Programme
BALLOON is funded by the Efficacy and Mechanism Evaluation Programme, an MRC and NIHR partnership, award NIHR156651.
Open research information
Protocol and trial registration
The protocol is published open access in BMJ Open. The ISRCTN record provides the public registration and trial-status information.
What happens when the trial finishes?
Results will be shared regardless of outcome.
Findings will be submitted to peer-reviewed journals and presented at national and international conferences. A parent-friendly summary should be sent to participating families and published here when the results are available.