Maurice Ralph Hilleman (b. August 30, 1919, Miles City, Montana – d. April 11, 2005, Philadelphia, Pennsylvania) was an American microbiologist who specialized in vaccinology and developed over three dozen vaccines, more than any other scientist. Of the fourteen vaccines routinely recommended in current vaccine schedules, he developed eight: those for measles, mumps, hepatitis A, hepatitis B, chickenpox, meningitis, pneumonia and Haemophilus influenzae bacteria. He also played a role in the discovery of the cold-producing adenoviruses, the hepatitis viruses and the cancer-causing virus SV40.
Early life and education
Hilleman was born on a farm near the high plains town of Miles City, Montana. His twin sister died when he was born, and his mother died the very next day. He credits much of his success to his work with chickens as a boy. Chicken eggs are used to develop vaccines based on weakened viruses.
When he was in the eighth grade, he discovered Charles Darwin, and was caught reading The Origin of Species in church. Due to lack of money, he almost failed to attend college. His eldest brother interceded, and Hilleman graduated from Montana State University on a scholarship. He won a fellowship to the University of Chicago and received his doctoral degree in microbiology in 1941.
After joining E.R. Squibb & Sons (now Bristol-Myers Squibb), he developed a vaccine against Japanese B encephalitis, a disease that threatened American troops in the Pacific Theater during World War II. As chief of the Department of Respiratory Diseases, Army Medical Center (now the Walter Reed Army Institute of Research) from 1948 to 1951, he discovered the genetic changes that occur when the influenza virus mutates, known as shift and drift. That helped him to recognize that an outbreak of flu in Hong Kong could become a huge pandemic. Working on a hunch, he and a colleague found (after nine 14-hour days) that it was a new strain of flu that could kill millions. Forty million doses of vaccines were prepared and distributed. Although 69,000 Americans died, the pandemic could have resulted in many more US deaths.
In 1957, Hilleman joined Merck & Co. (Whitehouse Station, New Jersey), as head of its new virus and cell biology research department in West Point, Pennsylvania. It was while with Merck that Hilleman developed most of the forty experimental and licensed animal and human vaccines he is credited with, working both at the laboratory bench as well as providing scientific leadership. In 1984, he retired from Merck as senior vice president of the Merck Research Labs.
In 1963, his daughter Jeryl Lynn came down with the mumps. He cultivated material from her, and used it as the basis of a mumps vaccine. The Jeryl-Lynn strain of the mumps vaccine is still used today. The strain is currently used in the trivalent MMR vaccine that he developed, the first vaccine ever approved incorporating multiple live virus strains.
Hilleman served on numerous national and international advisory boards and committees, academic, governmental and private, including the National Institutes of Health's Office of AIDS Research Program Evaluation and the Advisory Committee on Immunization Practices of the National Immunization Program. In his later life, Hilleman was an adviser to the World Health Organization.
Hilleman was an elected member of the US National Academy of Science, the Institute of Medicine, the American Academy of Arts and Sciences, and the American Philosophical Society. In 1988 President Ronald Reagan presented him with the National Medal of Science, the nation's highest scientific honor. He received the Prince Mahidol Award from the King of Thailand for the advancement of public health, as well as a special lifetime achievement award from the World Health Organization, the Albert Lasker Award for Clinical Medical Research and the Sabin Gold Medal and Lifetime Achievement Awards.
In March of 2005 the University of Pennsylvania School of Medicine's Department of Pediatrics and The Children's Hospital of Philadelphia, in collaboration with The Merck Company Foundation, announced the creation of The Maurice R. Hilleman Chair in Vaccinology.
Robert Gallo, co-discover of the virus that causes AIDS, once said “If I had to name one person who has done more for the benefit of human health with less recognition than anyone else, it would be Maurice Hilleman. Maurice should be recognized as the most successful scientist in history.” 
- Philadelphia Enquirer (August 30th, 1999 reprinted On the occasion of a large event around his 80th birthday
- Offit, Paul A. (2007), Vaccinated: One Man's Quest to Defeat the World's Deadliest Diseases, Collins, ISBN 0061227951.
- CounterPunch.org - 'Vaccines Don't Make the Same Profits for Big Pharma that Lifestyle Drugs Do -- Scientists or Celebrities?' Ralph Nader (April 16/17, 2005)
- NJABR.org - 'Dr. Maurice Hilleman, Vaccine Legend, dies at age 85', AMP News Service, New Jersey Association for Biomedical Research (April 14, 2005)
- WashingtonPost.com - 'Maurice R. Hilleman Dies; Created Vaccines', Patricia Sullivan, Washington Post (April 13, 2005)