The CAS Content Collection shows a steady increase in the number of journal articles and patents related to RNA applications in medicine (Figure ). The peak in patents in 2001-2002 may correlate with the first clinical trials using dendritic cells transfected with mRNA encoding tumor antigens (a therapeutic mRNA cancer vaccine) in 2001. The spike in journal article numbers in 2020 likely resulted from interest in the COVID-19 mRNA vaccines. The increase in journal articles and patents on therapeutic RNA from 2011-2016 can be attributed to initial interest in siRNA and miRNA, which decreased temporarily with the discovery of their off-target effects. Interest in mRNA also increased from 2011-2016, then decreased and only recovered once mRNA vaccines took center stage in the fight against COVID-19. Types of RNAs and their applications in medicine mRNA transcripts can act as therapeutic RNAs, diagnostic biomarkers, or therapeutic targets. Translation of an mRNA in the cell can produce a therapeutic protein to replace a defective or missing protein. In the case of vaccines, mRNA translation can generate antigenic targets for the immune system, such as the spike glycoprotein of SARS-CoV-2 in the COVID-19 mRNA vaccines. mRNA may also serve as a therapeutic target for ASOs, siRNA, miRNA, aptamers, and suppressor tRNAs.