Provided herein are microparticles and compositions comprising Poly(I:C) and/or polyinosinic acid (Poly I) and polycytidylic acid (Poly C) for use in preventing viral infections of the upper respiratory tract, such as human rhinovirus infection or an influenza virus infection. A nasal delivery device comprising a composition of the invention is also described.本文提供包含聚(I:C)及/或聚肌苷酸(聚I)及聚胞苷酸(聚C)之微粒及組合物，用於預防上呼吸道之病毒感染，例如人類鼻病毒感染或流行性感冒病毒感染。亦闡述包含本發明組合物之經鼻遞送裝置。
