Museum of Health Care Blog

The following blog post was contributed by Andrew Belyea, who is the Museum of Health Care’s 2017 Margaret Angus Research Fellow. Andrew has a degree in Life Science from Queen’s University and will start at the Queen’s School of Medicine in the fall.  This is Andrew’s fifth blog post in a series he will be writing throughout the summer. Special thanks to Trustees of the Estate of Larry Gibson, Graeme Fraser & Jay Rayner, for their generous support of this fellowship.

A General History of Inoculations

An understanding of disease resistance has existed in written records as far back as 429 BCE when the Greek historian Thucydides acknowledged that those who survived a smallpox epidemic in Athens were subsequently protected from the disease. Since a basic understanding of the biological underpinnings of infection was not understood for a long time, it was not until 900 AD when the Chinese developed a rudimentary smallpox inoculation. Chinese physicians noted how uninfected people who were exposed to a smallpox scab were less likely to acquire the disease or, if they did, that it was milder. The most common method of inoculation was to inhale crushed smallpox scabs through the nostrils.

In 1721, Lady Mary Montagu was the first to bring variolation to Britain when she inoculated her six-year-old daughter. The variolation procedure involved cutting open an arm to expose a vein and rubbing smallpox puss in the incision. This practice began to spread throughout England, gaining popularity throughout North America as well. In 1777, George Washington ordered mandatory variolation for all American troops who had never suffered from smallpox. Although a risky procedure, Washington acknowledged its benefits and fought against the Continental Congress, which had banned variolation among soldiers, following a successful mass inoculation program in Massachusetts.

In 1796, the English physician Edward Jenner demonstrated the effectiveness of inoculation to the greater world. Jenner had heard of dairymaids who, upon being infected by cowpox, were immune to the harsher infection of smallpox. On May 14, 1796, Jenner experimented with this concept by extracting puss from the hand of a milkmaid infected with cowpox. Jenner rubbed this puss into the scratched arm of an eight-year-old boy. Two months later on July 1, 1796, Jenner purposefully injected the boy with smallpox, which he never subsequently contracted. This successful experiment ushered in a new, scientifically based era of inoculation, and earned Jenner the informal title as the “father of immunology”.

It wasn’t until the 1880’s when chemist and microbiologist Louis Pasteur started to understand the true bacterial underpinnings of inoculations. When on vacation, Pasteur left his chicken cholera cultures unattended on the lab bench and, upon his return, injected his lab chickens with the virus. While this experiment had previously killed the chickens, the weakened virus now enabled the chickens to live. Following the success of this inoculation against fowl cholera, Pasteur used the same method to combat anthrax and rabies. In 1881, Pasteur inoculated 24 sheep, one goat, and six cows against anthrax while leaving a control group uninoculated. A few weeks later, he exposed both groups to anthrax – all vaccinated animals survived while none of the control group survived.

With all the excitement surrounding vaccinations as a cure-all for bacterial and viral diseases, a significant amount of research poured into the area in the late 19^th and early 20^th centuries. The early 20^th century produced vaccines for diphtheria, tetanus, whooping cough, and tuberculosis.

Vaccination Against the Spanish Flu

As J. J. Heagerty said in his September 1919 CMAJ article, “the strongest weapon in the hands of the health officer in the fight which he constantly wages against infectious disease is vaccination.”

When the flu hit eastern North America in the Fall of 1918, the idea of vaccinating as a treatment was already in the minds of many researchers. Although there were benefits to having myriad different vaccines produced at the same time, this made it challenging for health practitioners to determine which, if any, to provide patients. Most vaccines on the market claimed to be preventative, while a few also suggested therapeutic value. Because of the challenging choice physicians needed to make about which vaccine to use, many elected to use vaccines as a last resort rather than for their preventative value.

Edward C. Rosenow of the Mayo Clinic’s Division of Experimental Bacteriology argued in 1919 that mixed vaccines were the most effective form of inoculation. Mixed vaccines involved a combination of different bacteria in the same vaccine, and typically contained at least pneumococci and streptococci. Rosenow believed that the vaccine’s bacterial composition should mirror the current viral profile in the exact proportions that the bacteria were present. Because of this, his vaccines were in constant flux with changing component proportions. His vaccine was made widely available throughout the American upper Midwest and was completely adopted by the City of Chicago where 500,000 doses were produced.

Major Fred T. Cadham of Winnipeg gathered excellent epidemiological data on the use of a mixed vaccine at military camps in Manitoba. Since “the information [on vaccines], which could be derived at the time, was meager,” Cadham developed his own vaccine using naso-pharyngeal swabs from 128 cases of influenza. Smears were stained and cultures developed with five different bacterial species. An Emergency Military Hospital for Influenza in Tuxedo, Manitoba was proactively established with an anticipated increase in flu cases following vaccination. Table 1 shows the admission data for the hospital – notably, there were a similar number of admissions for inoculated and uninoculated cases, however there were more instances of pneumonia and death in uninoculated versus inoculated cases.

Table 1. Report of the Emergency Military Hospital for Influenza in Tuxedo, Manitoba (Source: Cadham, 1919)

Dr. Gordon Bell, the Chairman of the Manitoba Provincial Board of Health, granted permission for the production and distribution of 600,000 vaccinations throughout Manitoba and Saskatchewan. With a much larger sample size, Table 2 highlights the large-scale differences inoculation had in reducing the number of influenza, pneumonia, and death cases.

Table 2. Number and percent of influenza, pneumonia, and death cases among inoculated and uninoculated individuals given the Cadham vaccination.

This research supports the overwhelming attention vaccines were garnering during the influenza epidemic. Although there were a wide variety of vaccines being developed at the time, many of them shared a key underlying feature: most were effective at preventing, and in some cases treating, influenza. With improved communication between researchers in the early 20^th century, studying influenza in Kingston, New York, Tuxedo, or anywhere else meant results and encouragement could be shared more quickly. Although the transient epidemic meant influenza vaccines were focused on for only a few years between 1918-1920, the scientific principles and societal understanding of epidemics continues to have lasting impressions today. The research conducted on the Spanish Flu’s vaccine contributed immensely to the development of the annual flu vaccine that is now provided to millions annually.

To read more about the history of vaccines, visit http://www.medicaldaily.com/history-vaccines-variolation-378738

Heagerty article – Heagerty, J. J. “Influenza and Vaccination.” Canadian Medical Association Journal 9.3 (1919): 226–228. Print.

For more information on Major F.T. Cadham’s research, you can read his article published in the Canadian Medical Association Journal in September 1919 entitled “The Use of a Vaccine in the Recent Epidemic of Influenza.”