This is a multi-center, parallel, double-blind, randomized controlled clinical trial. Children <12 months of age hospitalized with bronchiolitis are randomized 1:1 to receive a 24-week home intervention with filtration units containing HEPA and carbon filters (in the child's sleep space and a common room) to improve indoor air quality (IAQ) or to a control group with filtration units without HEPA and carbon filters. The HEPA intervention units and control units will be used for 24 weeks after pre-intervention IAQ measurements. Children are followed for respiratory outcomes over the pre-intervention and intervention periods.

This is a multi-center, parallel, double-blind, randomized controlled clinical trial. Two hundred twenty-eight children <12 months old with their first hospitalization for bronchiolitis will be randomized 1:1 (stratified by site) to receive 24 weeks of home intervention with active HEPA filtration units to improve IAQ or to a control group without a HEPA or carbon filter inside identical-appearing units. Children will be followed for respiratory symptoms during a pre-intervention period of up to two weeks following randomization and during an intervention period of 24 weeks.

This study is designed to reduce barriers to participation for rural participants in that there will be no required study visits to a distant study site, and all study activities and data collection will be conducted remotely. Participants will be identified in hospitals in ISPCTN states, maximizing the chances that rural and medically underserved populations are represented. It is common for rural children with bronchiolitis to be transferred to tertiary care centers in urban/suburban locales, so inclusion of urban hospitals will allow for recruitment of this population.1 It is important for rural children to be represented in a bronchiolitis study in order to increase generalizability. Rural and underserved children have a higher risk of decreased access to medical care for symptoms and illness episodes, and a higher burden of asthma.83,84 These families may have air pollutant exposure profiles distinct from those residing in urban areas. For example, they might experience less exposure to traffic-related pollutants but may have more wood stove use or exposure to agricultural pollutants or wildfires. With its diversity of sites, the ECHO ISPCTN is well-positioned to enroll rural children that might otherwise be excluded.

Inclusion Criteria:

• Age <12 months at hospital admission
• First-time hospitalization for bronchiolitis
• One primary residence (>5 days per week)
• Parent, legal guardian or other legally authorized representative consents to allow their child to participate and agrees to participate in all study activities
• Electricity in the home (required to power the study equipment)
• Wireless internet access or cellular service access in the home*
• English or Spanish-speaking parent or guardian

Exclusion Criteria:

• Chronic airway or respiratory conditions requiring home oxygen, mechanical ventilation, or tracheostomy dependence; known immunodeficiency, hemodynamically significant cardiac conditions including those requiring medication or oxygen; cystic fibrosis; neuromuscular disease; eligible for palivizumab (per AAP guidelines87)
• Use of stand-alone home HEPA filtration other than study-related HEPA units in the home
• Household member who smokes (any type), vapes, or uses e-cigarettes
• Intention to move in the next 6 months
• Enrolled or plans to enroll in an interventional clinical trial for treatment of acute bronchiolitis or sequelae of bronchiolitis, unless permission given by the PI
• Another child in the household is enrolled in this study (one child per household can enroll)

The study team will place participant's de-identified data and other limited information, such as race and ethnic group, into one or more centralized database(s). The study team will share this data in compliance with the ISPCTN and NIH data sharing policies

NIH Public Access Policy ensures public access to the published results of NIH-funded research. Scientists are required to submit final peer-reviewed journal manuscripts from NIH funds to the digital archive PubMed Central upon publication acceptance.

ECHO ISPCTN Publications and Presentations Policy, ensures accurate, responsible, and efficient communication of findings from ECHO ISPCTN clinical trials. The ECHO ISPCTN Steering Committee has approved and ratified the Publications and Presentations Policy, which includes representatives from all site awardees, as well as representatives from NIH and the DCOC NIH Data Sharing Policy, the policy on the Dissemination of NIH-Funded Clinical Trial Information and the Clinical Trials Registration and Results Information Submission Rule. Trial results will be submitted to ClinicalTrials.gov. Additional plans are to publish results in peer reviewed journals. Researchers may request trial data by contacting Jeannette Lee, PhD, at the DCOC.

TBA

Families will be masked as to whether their Winix units are equipped with or without HEPA/carbon filters.

Study coordinators, investigators, and other team members who interact with participants' parent(s)/guardian(s) to obtain surveys, troubleshoot equipment setup and operation, or have other interactions will remain masked through the duration of the study for individual participants. This includes masking as to which intervention the participants receive and household air quality measurements, including the baseline measurements (separate personnel will need to be on the receiving end for air quality measurement data). This will require more than one study coordinator or additional staff/technician on the study team.