Compositions for coating microneedles with aluminum-adjuvanted vaccines are provided comprising an aluminum-containing wet gel suspension selected from aluminum hydroxide wet gel suspension and aluminum phosphate wet gel suspension； a vaccine in an amount effective to stimulate an immune response in a mammal； a sugar, sugar alcohol, or combinations thereof； and a thickener. Some embodiments of the compositions have a viscosity of 500 to 30,000 cps when measured at 100 s−1 and temperature of 25 C. Microneedle devices coated with the compositions, as well as methods of forming the compositions and coating the microneedles, and methods of maximizing the aluminum content of vaccine-coated microneedle arrays are also provided.
