Objective: Vaccines are considered a vital global healthcare commodity in the prevention and control of infectious diseases. According to the World Health Organisation, immunization has saved 154 million lives over the past 50 years. Traditional vaccines are typically administered with a needle and syringe through the subcutaneous or intramuscular route. Immunization through the mucosal surfaces, such as the lung, has the advantage of preventing initial infection by inducing an immune response at the site of pathogen entry. This research study investigated the challenges for the development and commercial adoption of mucosal vaccines inhaled through the lungs. Methods: This research adopted an interpretivist philosophy with an inductive approach. Qualitative data was collected by conducting 30-minute interviews with eight experts in vaccine and aerosol drug delivery research. The interviews were semi-structured with five questions. A thematic analysis was used to analyse the qualitative data collected. Results: The findings of this study confirmed that there are several challenges for vaccine delivery to the lungs. In this study, the themes identified included: compatibility of delivery devices, regulatory hurdles, safety concerns for lung administration, suitability of vaccine types, and the use of animal models for preclinical studies. Conclusion: Mucosal immunization by aerosolised vaccine delivery through the lungs has a promising future. This study identified opportunities for progression which included improved collaboration between vaccine researchers and medical device manufacturers, increased focus on diseases affecting the respiratory system, transparency of evidence to prove vaccine efficacy, and improved access to funding