Introduction: As underlined by the late 2019 outbreak of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), vaccination remains the cornerstone of global health-care . Although vaccines for SARS-CoV-2 are being developed at a record-breaking pace, the majority of those that are licensed or currently registered in clinical trials are formulated as an injectable product, requiring a tightly regulated cold-chain infrastructure, and primarily inducing systemic immune responses . Areas covered: Here, we shed light on the status of inhaled vaccines against viral pathogens, providing background to the role of the mucosal immune system and elucidating what factors determine an inhalable vaccine's efficacy . We also discuss whether the development of an inhalable powder vaccine formulation against SARS-CoV-2 could be feasible . The review was conducted using relevant studies from PubMed, Web of Science and Google Scholar . Expert opinion: We believe that the scope of vaccine research should be broadened toward inhalable dry powder formulations since dry vaccines bear several advantages . Firstly, their dry state can tremendously increase vaccine stability and shelf-life . Secondly, they can be inhaled using disposable inhalers, omitting the need for trained health-care personnel and, therefore, facilitating mass-vaccination campaigns . Thirdly, inhalable vaccines may provide improved protection since they can induce an IgA-mediated mucosal immune response.
Index: Dry powder vaccine, IgA, MALT, SARS-CoV-2, inhalation, mucosal immunity, pulmonary administration, respiratory viruses, vaccines