A Short History of Public Health Ideas
Some ideas are like dreams.
They arrive without warning, in the middle of the night or while you're showering. You can't always pinpoint their source. Maybe they spring from a conversation, or from something you've read, or from a failed experiment. Maybe you just had a hunch.
That seems to have been the case with Dr. John Snow, a British obstetrician, who laid the foundations for modern epidemiology with his idea about a pump. A skeptic of the theory that "bad air" was responsible for spreading disease, Snow traced the source of London's deadly 1854 Broad Street cholera outbreak to contaminated water from a community pump. Officials removed the pump handle and thus helped to halt the epidemic.
Of course, dreams - like ideas - can pose problems. While engineers were pursuing their dream of a canal across Panama, workers laboring to realize that dream were falling prey to tropical diseases. Scientists eventually seized on the idea that mosquitoes transmitted malaria and yellow fever, and the U.S. government launched an integrated mosquito-control program. These measures led to the elimination of yellow fever in the region and its subsequent reduction worldwide, and contributed significantly to antimalarial efforts that continue today, at U-M SPH and elsewhere.
While some ideas lead to treatments for disease, other ideas help prevent disease in the first place. Early attempts at variolation, or inoculating against smallpox (the Variola virus) by rubbing fluid from infected pustules into superficial scratches on uninfected individuals, occurred in Asia.
In 1796, English physician Edward Jenner developed the first-ever smallpox vaccine - a safer and more standardized alternative to the haphazard variolation technique. U-M SPH Professor Thomas Francis Jr. made vaccine history in the 1950s by demonstrating the efficacy of the Salk polio vaccine. He was also the key figure behind the first mass influenza vaccinations in the U.S.
But what if (that question beloved by children and scientists) you could prevent disease by vaccinating most, but not all, the members in a given community? That smart idea took hold in 1923, when epidemiologist A.W. Hedrich coined the term "herd immunity" to describe a phenomenon he'd observed during an outbreak of measles in Baltimore - that the spread of contagious disease is slowed or prevented when the majority of a community is vaccinated. Work by SPH Professor Arnold Monto in the landmark Tecumseh (Michigan) Community Health Study did much to establish the principle of herd immunity. Today the idea is fundamental to public health.
In public health, one idea is rarely enough. Take, for instance, the health of mothers and babies.
In 1915, approximately 100 infants per 1,000 live births in the U.S. died before reaching the age of one. By 1997, that rate had dropped by 90 percent - thanks in large part to sanitation improvements, safer drinking water, and a vast expansion of prenatal care under the 1935 Social Security Act. Today the SPH Office of Public Health Practice is working to reduce infant mortality by promoting equitable care in south-eastern Michigan.
Sometimes, as in the case of food safety, the best ideas stem from earlier ideas. Initially, Louis Pasteur's famous idea, pasteurization, was used only for wine preservation. But in 1924, the U.S. Public Health Service created a national standard for milk pasteurization - thus eliminating a potential source of foodborne illness. Since then, thanks to public health surveillance work and increased scientific knowledge, researchers have identified E. coli, Listeria, and Salmonella as causes of food poisoning in many commonly eaten foods. At SPH, Professor Ernst Siegenthaler contributed significantly to 20th-century improvements in food safety.
Additionally, the discovery and widespread understanding of vitamins, minerals, and basic food nutrients has led to substantial improvements in human nutrition. Among the most successful interventions are milk fortified with vitamin D to prevent rickets, niacin-enriched flour to prevent pellagra, folic acid in grain products to prevent neural tube defects in infants, and iodine in table salt to prevent goiter.
Many health challenges, like diabetes, are so big they require the combined talents and ideas of teams of individuals.
Before 1921, physicians had no means of preventing the toxic effects of excess blood glucose in people who lacked an insulin-producing pancreas. The rush was on to create a "pancreatic extract" that could serve in its place. Although several scientists worked contemporaneously on separate experiments, credit for the discovery of insulin goes to the Canadian team of Frederick Banting, J. J. R. McLeod, Charles Best, and Clark Noble, who cobbled together a purified extract that was dramatic in its ability to save lives.
Today insulin remains as vital in the lives of diabetics as when it was first introduced. Recently, SPH faculty have identified over 50 genes associated with diabetes - offering new hope for the prevention and treatment of this life-threatening disease.
The idea that we should reduce environmental hazards took hold in the U.S. in 1962 with the publication of Rachel Carson's Silent Spring.
The book led to a nationwide ban on pesticides and, in 1970, creation of the U.S. Environmental Protection Agency and passage of the Clean Air Act. Passage of the Clean Water Act in 1972 expanded the EPA's ability to monitor and regulate environmental pollutants. Through efforts like the U-M Air Quality Laboratory, SPH researchers have furthered EPA and other efforts to ensure a clean, healthy environment worldwide.
In 1964, the Advisory Committee to the U.S. Surgeon General published a landmark report stating that cigarette smoking was a cause of lung and laryngeal cancer in men, a probable cause of lung disease in women, and the leading cause of chronic bronchitis. During the 50 years since then, eight million premature deaths have been averted in the U.S. alone, thanks to the campaign to reduce tobacco use.
SPH Professor Kenneth Warner furthered these efforts with his 1985 study of the health implications of federal taxation of cigarettes and his testimony before the U.S. Senate, which helped sway Congress to extend the cigarette tax. Taxation is now one of the standard policy measures used as a disincentive to smoking. SPH faculty remain at the forefront of the ongoing fight against tobacco use.
Motor vehicles, too, are a part of our environment. By 1966, car crashes were a leading cause of unintentional injury and death. That year the U.S. government launched the first systematic efforts to promote motor-vehicle safety, including creation of the National Highway Safety Bureau. New government mandates required that vehicles include seatbelts and other safety equipment. These led to a rapid decline in traffic-related injuries and fatalities. Today SPH faculty are evaluating additional life-saving measures, including new graduated license programs.
Like dreams, some ideas go through multiple interpretations. That's the case with health insurance, an idea that originated with ancient Greek and Roman "benevolent societies," which paid for members' funeral expenses and provided for their survivors.
This model informed the establishment of health insurance in the U.S. in the 19th century. Early plans offering coverage for steamboat and train accidents evolved into rudimentary group policies covering a range of benefits. In 1939, SPH Professor Nathan Sinai developed a voluntary health insurance plan that became a prototype for Blue Shield. Nearly a century later, SPH experts in health policy contributed to the development of the Affordable Care Act.
These are just a smattering of the ideas that have made public health what it is today. Our field is full of dreamers who are hatching new ideas even as you read these words.