Besides vaccines, what other applications does mRNA have?

Besides vaccines, mRNA can also be used in these therapeutic applications: 

Gene therapy - Using mRNA for gene therapy poses fewer risks as compared to conventional gene therapy techniques to cure diseased cells. mRNA-based gene therapy is used in several applications in the treatment of neurological disorders.

Protein replacement therapy– Absence of a specific protein or compromised function of the protein can cause several different human diseases. When the impacted protein is encoded with mRNA and delivered therapeutically it can restore function to healthy levels. The main advantages of mRNA protein therapy over conventional protein therapy is the longevity of treatment.

Antibody therapy – mRNA antibody therapy is a more cost-effective and practical alternative to traditional antibody therapy. Another significant benefit is that it enables prolonged patient therapy as compared to the very limited duration of protein therapy, 

Colorectal cancer treatment – Studies are still being done to explore ways to use mRNA technology to overcome the limitations of surgery, which often fails to eliminate all the cancer cells from the body even after the tumor is removed. 

Cure for Autoimmune Disease – In the treatment of autoimmune disease, mRNA technology helps to boost immune cell tolerance and reduce damage without compromising the normal immune system function.

Customized Cancer Vaccines – mRNA offers a superior approach for targeted therapies. It can be used to express neoantigens (tumor-associated epitopes) in host cells in order to create customized cancer vaccines. On being presented by the host cell, the immune system is able to recognize the antigen and produce an effective response against the cancer.