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 100s
