An Open-label, Non-drug Methodology Trial to Evaluate the Use of a Mouthpiece With the VR647 Inhalation System During Delivery of Isotonic Saline (0.9% NaCl) in Subjects Less Than Five Years of Age Who Have Previously Received an Inhaled Therapy Delivered Either by a Nebulizer or by a Pressurized Metered-dose Inhaler Plus Spacer

Study start date: November 3, 2017

Inclusion Criteria: * Male or female subjects aged 1 to \<5 years * History of coughing and/or recurrent wheezing within the last year, otherwise healthy * Use of an inhaler with a spacer or nebulizer for at least 30 days (consecutive or otherwise) within the last year. Examples of inhaled or nebulized therapy include the use of a regular controller (inhaled corticosteroids (ICS) or ICS/long-acting beta-agonists), or a reliever therapy (e.g., albuterol) on an as needed basis for the relief of symptoms * Written informed consent from the subjects's parent(s)/legal guardian(s), including privacy authorization, prior to trial participation * Subject's parent(s)/legal guardian(s) must be willing and able to comply with the trial procedures and visit schedules Exclusion Criteria: Screening (Visit 1) * Any significant medical conditions (apart from a history of coughing and/or recurrent wheezing) that in the opinion of the investigator would interfere with the subject's ability to use the mouthpiece and/or follow the protocol procedures * Subjects with current respiratory symptoms or breathing difficulties at the time of screening * History of paradoxical bronchospasm or hyper-responsiveness following inhaled therapy that in the opinion of investigator may put the subject at risk when inhaling isotonic saline * Parent(s)/legal guardian(s) who is an employee of the investigational site or the Sponsor, who is directly involved in the trial, or a family member of such a person Nebulization Assessment 2 (Visit 2) * Development of any new illness or condition between the Screening (Visit 1) and prior to Nebulization Assessment 2 (Visit 2) that in the opinion of the investigator would interfere with the subject's ability to use the mouthpiece and/or follow the protocol procedures * Any safety concerns that in the opinion of the investigator would jeopardize the subject by his/her continued participation in the trial