Respiratory Delivery of Probiotics to Improve Lung Health

Increasing evidence suggests that the lung microbiome is essential for maintaining lung health and homeostasis. Although causality has not been established, differences in its abundance, community richness, and composition are observed in inflammatory lung diseases such as asthma. Furthermore, respiratory infections such as COVID-19 were shown to influence the composition of the lung microbiome. The efficacy of inhaled probiotics to correct this dysbiosis is unknown as the respiratory route of administration is less reported compared to the oral route. The more direct intranasal administration of probiotics may exert a greater protective response against viral respiratory infections compared to the oral route in mice. However, there is a lack of human studies investigating the efficacy of inhaled probiotics. This may be due to the limitations in administration methods in delivering probiotics to humans, as to date, only a nasal spray or a nasal irrigation has been utilised. Nasal sprays require the probiotics to be in a liquid suspension which can affect the longevity of the product. Therefore, investment into developing a more stable probiotic formulation is needed.