Abstract: Described herein are compositions and methods for the reducing a risk of contracting a respiratory disease in a subject or reducing a risk of transmitting a respiratory disease from a first subject to a second subject. In some cases, a composition or method described herein can comprise a modulator (e.g., a pattern recognition receptor, such as a STING agonist, for instance cGAMP) In some cases, a composition or method described herein can comprise a liposome, which may be used to encapsulate one or more STING agonists. In some cases, a liposome of a composition or method described herein may comprise one or more antigens attached to, integrated into, or associated with a liposomal membrane of the liposome.