Jeryl Lynn comforts her crying sister Kirsten during a 1966 vaccination with the Jeryl Lynn Strain.
In 1963, vaccine researcher Dr Maurice Hilleman was working to develop a safe and effective vaccine against mumps when his five-year-old daughter, Jeryl Lynn, developed the disease. One night, Jeryl Lynn woke Hilleman and showed him her swollen cheeks, a characteristic sign of mumps. He then swabbed her throat to collect a sample of the virus and drove it to his laboratory. Hilleman was the chief virologist at Merck Research Laboratories in the 1960s and had set out to create a mumps vaccine. At the time, mumps was considered a common childhood illness, and many parents underestimated its dangers. According to the Smithsonian’s National Museum of American History, scientists had already tried to develop a vaccine, but earlier attempts had problems. Some vaccines caused too many mumps symptoms, while others did not provide enough immunity. Jeryl Lynn’s infection gave Hilleman a chance to try a different approach. He suspected that he needed to work with another strain of the virus. After collecting the sample from his daughter, he began trying to weaken the virus, a process known as attenuation. The aim was to make the virus weak enough that it would not cause mumps, while still allowing it to produce immunity. Hilleman achieved this by introducing the virus to generations of chicken embryo cells. With each generation, the virus changed. It became better at attacking the chick cells and less able to attack human cells. The resulting vaccine strain was officially named the Jeryl Lynn Strain, after the child whose infection provided the original virus sample.
From Jeryl Lynn’s infection to a vaccine
Human testing showed that the Jeryl Lynn Strain vaccine could produce strong immunity without causing the disease in vaccinated children. The work then moved towards clinical use, including a remarkable connection within the Hilleman family. Jeryl Lynn herself could not benefit directly from the vaccine that carried her name. Her younger sister, Kirsten Jeanne Hilleman, did. In 1966, Kirsten was immunised with the investigational vaccine. A photograph from that year shows Jeryl Lynn comforting her younger sister as Kirsten received the vaccine from Dr Robert Weibel. The Smithsonian says the vaccine was developed from the virus collected from Jeryl Lynn’s mumps infection. Its collection also includes vials of the investigational vaccine used to immunise Kirsten. In 1967, the US Food and Drug Administration approved Merck’s mumps vaccine. The vaccine developed by Hilleman remains in use today and is still derived from the Jeryl Lynn strain. The Smithsonian also notes that doctors began administering the Jeryl Lynn Strain mumps vaccine to the American public in early 1968.
A mumps quarantine sign dating to sometime after 1909.
Why the mumps vaccine mattered
The vaccine was developed against a disease that could cause more than the familiar swelling of the jaw and cheeks. Most people who contract mumps recover fully, but the disease can also lead to serious and sometimes permanent complications. These include inflammation of the testicles and ovaries, encephalitis, which is swelling of the brain, meningitis, which is infection of the tissue around the brain and spinal cord, seizures and deafness. Before vaccination, mumps was also a significant cause of acquired deafness in childhood in the United States. The Smithsonian noted that the disease was once so common that it was often treated as a normal part of growing up, even though it could have serious consequences. The museum marked 50 years of mumps vaccination in America in 2018. It described how the vaccine helped make the swollen cheeks associated with mumps a thing of the past for many Americans. The change was also reflected in popular culture. The Smithsonian holds two Norman Rockwell prints from around 1972 that were commissioned by Merck Research Laboratories to celebrate vaccination and the changing American experience of childhood disease. One of the works shows a family having to cancel a fishing trip after their son develops mumps.
The virus sample was kept for decades
The story of the Jeryl Lynn Strain did not end with the vaccine’s development. The Smithsonian later acquired an object connected to the preservation of the virus stock used for vaccine production. The museum acquired a shiny stainless-steel 15-litre canister that had stored part of the frozen Jeryl Lynn virus “seed stock”. It was one of five canisters used to keep the entire supply safe and pure. According to the Smithsonian, the stock kept in the canister could produce 3.26 billion doses of vaccine. The container had protected the stock for years, but its green neoprene stopper eventually began to fail. That created a problem because the virus stock had to be moved without becoming contaminated or losing its potency. In 2015, Merck scientists undertook the task of thawing and transferring the precious seed stock into new containers. The Smithsonian said that if the stock had lost its potency or become contaminated during the transfer, it could have taken five to seven years to produce new stock. The transfer was successful. The Jeryl Lynn stock was moved into a more secure type of container, while the old stainless-steel canister became part of the Smithsonian’s collection.
