Gertrude Belle Elion was a twentieth-century scientist in the US who researched the structure of viral DNA to help develop anti-viral medications. For her work on drug development, Elion was a co-recipient of the 1988 Nobel Prize in Physiology or Medicine, even though she lacked a PhD or MD. In the 1970s, Elion helped to develop acyclovir, an early anti-viral medication, alongside a team of other researchers. Acyclovir was one of the first selective medications to effectively treat herpes simplex virus types 1 and 2, or HSV-1 and HSV-2. Those are common viruses that can be transmitted via close contact or sexual intercourse, and cause sores on the mouth and genitals. The medications that Elion helped develop were also some of the first to specifically inhibit the replication of viral DNA. By creating medications like acyclovir based on her knowledge of chemistry and biology, rather than through trial and error, Elion helped create a new model for drug development, in addition to making an effective treatment for herpes, which afflicts billions of people globally, and can cause life-threatening illness in infants.

George Herbert Hitchings researched and developed medications that targeted specific parts of DNA replication processes to treat cancers and various illnesses in the US during the twentieth century. By studying DNA analogs, or manmade substances that resemble the structure of naturally occurring DNA components and are capable of inhibiting DNA replication, Hitchings promoted a novel approach to pharmaceutical research and drug development, known as rational drug design. Using that novel approach, Hitchings and his research team created acyclovir, one of the first medications to effectively treat herpes, a condition that can be sexually transmitted but can also be passed from mother to child, causing life-threatening illness in infants. Hitchings also contributed to the development of cancer treatments, immunosuppressant medications, anti-viral medications, and anti-malarial medications. Hitchings’s research on DNA analogs established rational drug design as a method to create new pharmaceutical drugs, some of which treat sexually transmitted illnesses.