Maurice Ralph Hilleman (August 30, 1919 – April 11, 2005) was a leading American microbiologist who specialized in vaccinology and developed over 40 vaccines, an unparalleled record of productivity.

His eldest brother interceded, and Hilleman graduated first in his class in 1941 from Montana State University with family help and scholarships.

Hilleman showed that these infections were actually caused by a species of bacterium, Chlamydia trachomatis, that grows only inside of cells.

As chief of the Department of Respiratory Diseases at Army Medical Center (now the Walter Reed Army Institute of Research) from 1948 to 1957, Hilleman discovered the genetic changes that occur when the influenza virus mutates, known as antigenic shift and Antigenic drift, which he theorized would mean that a yearly influenza vaccination would be necessary.

[2][23] In 1957, Hilleman joined Merck & Co. (Kenilworth, New Jersey), as head of its new virus and cell biology research department in West Point, Pennsylvania.

It was at Merck that Hilleman developed most of the forty experimental and licensed animal and human vaccines for which he is credited, working both at the laboratory bench as well as providing scientific leadership.

[7][16] In 1968, during the Hong Kong flu pandemic, Hilleman and his team also played a key role in developing a vaccine, and nine million doses became available in 4 months.

[28] He and his group invented[4] a vaccine for hepatitis B by treating blood serum with pepsin, urea and formaldehyde.

For a time, he kept a row of "shrunken heads" (actually fakes made by one of his children) in his office as trophies representing each of his fired employees.

He used profanity and tirades freely to drive his arguments home, and once, famously, refused to attend a mandatory "charm school" course intended to make Merck middle managers more civil.

[34] In March 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.

[citation needed] Robert Gallo, co-discoverer of HIV (the virus that causes AIDS), said in 2005: "If I had to name a person who has done more for the benefit of human health, with less recognition than anyone else, it would be Maurice Hilleman.

"[8] In 2005, Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, said that Hilleman's contributions were "the best kept secret among the lay public.

"[7][35] In 2007, Paul Offit published a biography of Hilleman, entitled Vaccinated: One Man's Quest to Defeat the World's Deadliest Diseases.

In 2007, Anthony S. Fauci wrote in a biographical memoir of Hilleman:[7][36]Maurice was perhaps the single most influential public health figure of the twentieth century, if one considers the millions of lives saved and the countless people who were spared suffering because of his work.

Subsequent awardees were Samuel L. Katz (2010),  Albert Z. Kapikian (2011), Myron Levine (2012),  Emil Gotschlich and R. Gwin Follis-Chevron (2013), Dan M. Granoff (2014), Peter Palese (2016) and Stephen Whitehead (2018) In 2016, a documentary film titled Hilleman: A Perilous Quest to Save the World's Children, chronicling Hilleman's life and career, was released by Medical History Pictures, Inc.[39] In 2016, Montana State University dedicated a series of scholarships in memory of its alumnus Hilleman, called the Hilleman Scholars Program,[40] for incoming students who "commit to work at their education beyond ordinary expectations and help future scholars that come after them".