Pearl Luella Kendrick researched prevention for pertussis, commonly known as whooping cough, in Grand Rapids, Michigan, during the mid-1900s. Pertussis is a respiratory disease that mainly affects infants and young children. During the 1920s, pertussis was responsible for more deaths in children in the United States than any other disease. In the 1930s, Kendrick created one of the first pertussis vaccines that underwent large-scale clinical trials. Towards the end of her career, Kendrick helped developed combination vaccines for other common childhood diseases at the time, including diphtheria, tetanus, pertussis, and poliomyelitis. She also studied immune responses in infants whose mothers had pertussis antibodies that transferred to them during pregnancy. Kendrick helped lower the incidence and death rate of pertussis and other common childhood diseases in the US through the creation of vaccines.

The measles, mumps, and rubella (MMR) vaccine was created by Maurice Hilleman in 1971 at the Merck Institute of Therapeutic Research, a pharmaceutical company in West Point, Pennsylvania. It combined three separate vaccines for measles, mumps, and rubella, common and sometimes fatal diseases. Measles causes a red skin rash and severe fevers that can be fatal. Mumps causes fever and swelling of the salivary glands in the mouth and jaw, while rubella causes milder fevers and skin rashes. Pregnant women that contract rubella sometimes pass the virus to their fetuses, causing congenital rubella syndrome, which results in malformations of the eyes, ears, heart, and brain in the fetuses. The MMR vaccine has protected millions of people from contracting the potentially deadly diseases of measles, mumps, and rubella, as well as prevented the development congenital rubella syndrome in the fetuses.

Maurice Ralph Hilleman developed vaccines at the Merck Institute of Therapeutic Research in West Point, Pennsylvania, during the twentieth century. Over the course of his career at Merck, Hilleman created over forty vaccines, making him one of the most prolific developers of vaccine in the twentieth century. Of the fourteen vaccines commonly given to children in the US by 2015, Hilleman was responsible for eight of them. Hilleman's most widely used vaccine was his measles, mumps, and rubella (MMR) vaccine. Hilleman's MMR vaccine prevented many diseases and also rubella in millions of children and pregnant women. Rubella in pregnant women often led to congenital rubella syndrome in the fetus, causing severe malformations.

Stanley Alan Plotkin developed vaccines in the United States during the mid to late twentieth century. Plotkin began his research career at the Wistar Institute in Philadelphia, Pennsylvania, where he studied the rubella virus. In pregnant women, the rubella virus caused congenital rubella syndrome in the fetus, which led to various malformations and birth defects. Using WI-38 cells, a line of cells that originated from tissues of aborted fetuses, Plotkin successfully created RA27/3, a weakened strain of the rubella virus, which he then used to develop a rubella vaccine. Plotkin’s rubella vaccine has prevented birth defects due to congenital rubella in developing fetuses and newborns.