Methods for long-term vaccine storage without significant immunogenicity loss, especially without refrigeration, are important for vaccination campaigns. Microneedles are coated with vaccine in the solid state, which is expected to confer thermal stability. In a stability study of microneedles coated with inactivated influenza vaccine, mice immunized with coated microneedles stored at room temperature for 1 month produced similar IgG responses to those of mice immunized by microneedles stored for 1 day. Furthermore, both groups were completely protected from lethal challenge after viral infection. In vitro assay of the microneedles, however, showed a decrease in antigenicity by about 80% (Kim et al. 2010c ).