Endonasal filters for the prevention and control of respiratory allergy and infections. A multi-stakeholder assessment.

Healthcare innovations aim to develop and provide technologies, services, and health policies to improve population health and well-being at a global level. Among innovative medical devices (MD), endonasal filters (EF) are designed to improve breathing and capture fine dust and allergens in the surrounding environment acting as a mechanical barrier to the passage of allergens, pathogenic microorganisms and dust. This paper aimed to: i) review the features of EF commercially available, regulatory classification, and their potential role in public health as useful innovative devices; ii) review their role in prevention and control of respiratory infections; iii) review their role in prevention and control of allergic respiratory diseases. A review of MD on the market was carried out through official Ministry of Health, commercial and pharmaceutical channels. Moreover, three separate literature reviews were done by the involved multidisciplinary team. The analysis of the European market, with particular attention to Italy, on available MD identified seven brands of EF. A search conducted at 16th April 2023 in Italian MD Database of the Ministry of Health revealed that three products were registered as MD and they were available on the Italian market. Literature review found 3 studies on nasal filter technical description, 4 studies on patients on infectious diseases and other applications, and 13 studies on patients on respiratory allergy. Studies on infectious diseases were one review, and one correspondence reporting a research proposal. Studies on respiratory allergy included 3 randomized controlled studies, 5 observational open-label non-randomized studies, 2 case series, 1 case report, 1 review, and 1 systematic review. Despite reasonable theoretical fundamentals to claim that EF might contribute to the reduction of infection viral load, current evidence supporting the use of such filters is still scarce, suggesting the need to further research and comprehensive assessments for developing ad hoc documents, guidelines and recommendations.