Pioneers in the Fight Against Polio Thomas Francis Jr. ’21 and William Hammon ’32
by Erin Lukehart ’00
When Thomas Francis Jr. ’21 made his historic announcement at the University of Michigan on April 12, 1955 that the Salk polio vaccine had proven “safe, effective, and potent,” the world was watching. From the late nineteenth century and into the twentieth, communities braced for the annual polio epidemics that struck each summer, infecting tens of thousands of victims—many of whom were children, often left paralyzed. Francis’s announcement meant the first major step toward eradication of the disease.
What many don’t know is that another Alleghenian, William Hammon ’32, also played an important role in polio prevention.
Although graduating eleven years apart, Hammon and Francis had much in common. Both were raised in western Pennsylvania—Francis graduating from New Castle High School and Hammon from Schenley High School in Pittsburgh—and each would go on to pursue groundbreaking research in newly formed schools of public health.
Both served leadership roles in the Armed Forces Epidemiological Board (AFEB), which was established to bring together civilian scientists and their military counterparts for research purposes. The first director of the AFEB’s Commission on Influenza, Francis was later named board president from 1958 to 1960. Hammon served on the AFEB Commission on Virus Diseases from 1956 to 1965 before being instated as a full board member in 1965.
Most important, both men would forge a relationship with Jonas Salk, who ultimately developed the first successful polio vaccine. But the nature of each relationship was quite different—Francis in the role of Salk’s mentor and Hammon in the role of Salk’s research rival. Those relationships not only affected the development of the polio vaccine but also shaped the future of public health.
In a paragraph under his senior year photograph in Allegheny’s 1921 Kaldron, Francis is described as a “bundle of energy, a favorite with the ladies.” Noting Francis’s budding interest in medicine, the writer predicts that “his smile will bring the suffering ones back to health.”
Francis earned his medical degree from Yale in 1925 before launching his research career with the Rockefeller Institute, where he became the first American to isolate human flu virus. He continued influenza research as a bacteriology professor in the School of Medicine at New York University, where he mentored a young student named Jonas Salk.
Francis developed a strong reputation in his field—in the same year he was asked to head the AFEB’s Commission on Influenza, he was also recruited to join the faculty at the University of Michigan’s School of Public Health and Medical School. At the university’s Department of Epidemiology, Francis built a virus laboratory and crossed paths again with Salk, who had come to Michigan to pursue postgraduate studies.
Commissioned by the AFEB, Francis and Salk worked together to create and test what was ultimately a successful vaccine for influenza. Francis’s use of the “killed virus” model for vaccination proved influential when Salk began to develop a vaccine for polio years later.
After finishing his degree and completing a short teaching stint at Michigan, Salk was recruited to join the faculty at the University of Pittsburgh School of Medicine. When the university opened a new school of public health in 1948, Salk was eager to take on the chairmanship for the Department of Infectious Diseases and Microbiology. To Salk’s chagrin, however, the position was awarded to William Hammon.
Although Hammon’s photograph is missing from Allegheny’s 1932 Kaldron, the yearbook indicates he was a member of the Allegheny Singers, the band, and also the Thoburn Club, a religious organization. He was an ordained Methodist minister, briefly serving as a missionary to the Belgian Congo after graduating from Allegheny.
Hammon received not only a medical degree from Harvard but also a master’s degree in public health in 1938 and a Ph.D. in 1939. While studying there, he was mentored by the well-regarded bacteriologist and epidemiologist Hans Zinsser, and he worked with future Nobel Prize winner John Enders to develop the first vaccine for feline panleukopenia. He was soon recruited to teach at the University of California at Berkeley.
By the time Hammon joined the University of Pittsburgh faculty in 1948, Salk had already begun his historic polio research. Salk’s efforts were supported by the National Foundation for Infantile Paralysis (NFIP), an organization established by Franklin Delano Roosevelt in 1937 that would later become the March of Dimes.
Shortly after arriving in Pittsburgh, Hammon announced his own plans to research polio prevention. Hammon favored “passive immunization,” in which blood gamma globulins are injected into the body to transfer antibodies to fight the virus. Rather than preventing actual infection, this method aims to keep the virus from taking hold of the nervous system and producing the disease’s dreaded symptoms once an outbreak has already occurred. Hammon believed that live or killed virus vaccines were too risky, based upon earlier research in which some subjects had developed illness or experienced serious allergic reactions.
Hammon’s initial attempts to gain support for a field trial had failed—the NFIP was not convinced that his method was viable (it is noteworthy that one of those NFIP-affiliated detractors was Jonas Salk). But after another year of animal and human studies, Hammon was given approval to begin field trials in 1951. He led what is considered to be the first large-scale double-blind placebo-controlled trials, in which neither the patients nor the health workers knew which injections were real or placebo. Francis later employed this method for the Salk vaccine field trials.
Based upon Hammon’s field trials, gamma globulin was found to be reasonably successful in preventing polio’s symptoms— or at the very least, helped to reduce the severity of the virus’s effects on the body. The press and medical community hailed Hammon for his findings, but the praise was short-lived.
Hammon’s trials had depleted much of the nation’s gamma globulin supply already, and since he was largely relying upon donated blood, there simply wouldn’t be enough for large-scale usage. The equipment was costly, and ultimately immunity was not permanent—a new injection would be required during each polio outbreak.
Hammon conceded that gamma globulin would be most effective for small groups of people in specific locations when outbreaks occurred and that a permanent vaccine would be a better option. Indeed, the medical community was beginning to take notice of Salk’s research by the spring of 1953, and in that same year he approached Francis to implement the nationwide field trials of the vaccine.
This year marked the fiftieth anniversary of Francis’s announcement of the vaccine’s effectiveness. In honor of his many contributions to public health, the University of Michigan presented its first Thomas Francis Jr. Medal in Global Public Health to William Foege. Foege, who pioneered a successful strategy to eradicate smallpox in the 1970s, is the former chief of the Centers for Disease Control and director of the Carter Center.
Beyond his connection to Salk’s polio research, Francis continued a brilliant career in epidemiology until his death in 1969. These later efforts include the “Tecumseh Study,” in which Francis studied chronic diseases in terms of geography, history, and local culture in order to understand ways in which scientists might predict how these diseases develop.
Although Hammon’s polio research has long since been overshadowed by the work of Salk and, later, Alfred Sabin, his contributions are enduring. Gamma globulin is still used today for passive immunity against infectious diseases like measles, hepatitis A and B, and rabies, among others. Hammon died in 1989.
As predicted by the anonymous writer in the Kaldron so many years ago, Francis—and Hammon, as well—contributed a lasting legacy in efforts to “bring the suffering ones back to health.”
This article can be found in the Summer 2005 issue of Allegheny Magazine.