Immunization History: Smallpox, Edward Jenner and Mary Montagu
Smallpox is a historically devastating disease that has probably been eliminated in nature. The virus that causes the disease still exists in laboratories, however. The last case of smallpox produced by natural causes (as far as we know) was diagnosed on October 26th, 1977. A young man in Somalia developed the disease. Happily, he survived. In 1979, the World Health Organization declared that smallpox had been eradicated.
A chilling reminder that smallpox could appear again occurred in 1978 when a lab accident in England released the virus. One person died from the resulting infection, which was limited to a small number of people. Today the virus officially exists in just two laboratories - one in the United States and the other in Russia - and is kept under secure conditions.
The smallpox virus hasn't been destroyed, despite the potential dangers of its existence. Scientists want to have access to the virus so that they can study it and create a new vaccine if this is necessary. Hopefully no more infections will occur, but the possibility exists.
In the past, the word "pox" referred to a disorder that caused skin eruptions. Smallpox was given its name in comparison to the great pox, or syphilis.
What is Smallpox?
There are two species of the smallpox virus. In the past, Variola major was the most common species in nature and caused the most serious form of the disease. The death rate from the infection was 30% to 35%. Variola minor was less common and caused a milder form of the disease. The death rate from an infection by this species was only 1%.
The first symptoms of smallpox appear ten to fourteen days after the initial infection. The person experiences a general feeling of being unwell and may also experience a backache, fever, a severe headache, vomiting, diarrhea and/or delirium. In addition, the virus causes fluid-filled pustules to appear on the skin. After about eight days the pustules develop crusts and begin to fall off. Most survivors of smallpox are left with scars on their skin. They may also suffer from complications such as blindness and arthritis.
Mary Montagu (1689-1762) discovered the process of variolation while Edward Jenner (1749-1823) discovered vaccination. The term "discover" isn't completely accurate, however, since both variolation and vaccination had been used to prevent smallpox before Montagu and Jenner publicized their techniques.
Variolation Compared to Vaccination
Variolation is the process of infecting someone with a mild form of smallpox in order to give them immunity to a serious form of the disease. The name of the process comes from Variola, the scientific name of the smallpox virus.
In its original meaning, vaccination meant infection by materiał from pustules found on a cow. The Latin word for cow is "vacca", and the word "vaccinus" means "of the cow". These terms gave vaccination its name. The virus transferred from the cow pustules in the first vaccinations may have been the cowpox virus. This is a relative of the smallpox virus but causes a much milder disease. The cowpox virus stimulates the immune system to produce antibodies that also fight the smallpox virus, giving the person immunity.
Today it's uncertain whether the transferred virus in Edward Jenner's experiments was the cowpox virus or the very similar vaccinia virus. The vaccinia virus produces a mild disease and gives immunity to smallpox. It's used in the modern smallpox vaccine. The origin of this virus is unknown. It may have developed from the cowpox virus, but the moment in history when this happened is unknown.
Mary Wortley Montagu
Lady Mary Wortley Montagu was born in 1689. Her father was Evelyn Pierrepont, 5th Earl and 1st Duke of Kingston-upon-Hull. Her mother, Lady Mary Fielding, was a relative of the novelist and playright Henry Fielding. Mary grew up with a great love of reading and writing as well as a belief in women's rights.
In 1712, Mary married Edward Wortley Montagu. She had a reputation for beauty and wit and was a popular visitor to the Royal court. However, in December 1715 she became infected with the smallpox virus. This left her with a severely scarred face. Her brother had already died from smallpox in 1713, so Mary was very familiar with the disease.
In 1716, Mary's husband became the ambassador to Turkey. Mary and her son (born 1713) accompanied Montagu on his journey to Turkey. Mary quickly began to explore her new home and was the first European woman to visit many of the areas that she investigated. She learned to speak some Turkish and studied the local culture with interest and respect. Her enthusiastic and careful observations of the lives of Turkish women were recorded in a series of letters. The letters were published and established her reputation as a great travel writer and observer.
What is Variolation?
Lady Mary Wortley Montagu and Variolation
Mary was very impressed with the way in which Turkish women protected their children from smallpox, a process which she called engrafting. The women took pus from a blister of someone with a mild form of the disease and then injected it into their children with a large needle. The children became sick, but not seriously so. When they recovered they were resistant to smallpox. Mary was so excited by the process that she had her son immunized in the same way.
In 1718, Mary gave birth to a daughter. She returned to England later that year. Smallpox was a common infection at that time and was one of the leading causes of death from infection. Mary asked Charles Maitland, an English doctor who she had met in Turkey, to immunize her daughter by engrafting. Reluctantly, he did so. The process was successful.
Some people developed a severe case of smallpox after variolation. The procedure became popular, however, because it was obvious that the risk of death from variolation was much lower than the risk of death from smallpox.
Mary began a campaign to promote the use of variolation in England. She publicized the inoculations and the health of her children extensively. Members of the aristocracy became interested in the new procedure and some of them had their children variolated.
Mary obtained a powerful ally in the form of Caroline, Princess of Wales. The princess combined her efforts with Mary's in an attempt to test variolation on condemned prisoners, who were promised a pardon if they agreed to the test. The women achieved their goal and the prisoners became immune to smallpox. Variolation was then tested on orphan children and was found to be successful. In an amazing show of confidence, King George l allowed Dr. Maitland to variolate two of his grandchildren, who were the children of the Prince and Princess of Wales. The variolation was once again successful, as it was in many people who received the treatment.
Dr. Edward Jenner spent most of his life practicing medicine in Berkeley, Gloucestershire. As a child he had received a variolation treatment at school, which had been a very unpleasant experience. The children went through a harsh preparation period before they were variolated. Jenner wanted to find a better way of preventing smallpox.
Jenner noticed that dairy maids and other people who regularly milked cows seemed to be immune to smallpox. He realized that people who had caught cowpox from the cows didn't get smallpox. Jenner's observations and deduction had been made by other people before him, and other people had transferred pus from cow pustules to humans to confer immunity to smallpox. It's unknown if Jenner had heard of the previous discoveries. He wanted to scientifically prove that a cowpox infection could prevent smallpox.
Edward Jenner's First Experiment
James Phipps and the Smallpox Experiment
To prove his hypothesis, Jenner performed an experiment which would never be allowed today. James Phipps was the eight-year-old son of a poor laborer who sometimes worked for Jenner. The doctor injected the boy with pus obtained from a cow pustule. Once the boy had recovered from the resulting infection, Jenner infected him with pus from smallpox blisters. Even after repeated tests, the boy didn't develop smallpox. By infecting James with the cow virus, Jenner had given him a vaccination against smallpox.
Jenner wrote a paper describing his research and tried to get it published by the Royal Society, a highly respected organization of scientists which still exists today. The society told him that more proof was needed. The thought that people would need to be injected with material from a cow in order to prevent smallpox was very unsettling for many people. The Society was almost certainly worried about the public's response. Jenner repeated his experiment with many more children. None of them developed smallpox. Jenner's research was finally published by the Royal Society.
Public Outrage over the Cowpox Vaccine
Many people reacted to Jenner's publication in outrage. Clergymen said that the injection of pus from a sick cow was a repulsive idea. A popular cartoon of the time (shown above) depicted people changing into cows as they received a vaccination. Nevertheless, the huge advantage of preventing smallpox in a safer and more effective way than variolation eventually overcame people's objections. Today Edward Jenner is known as the Father of Immunology. Immunology is the study of the immune system.
Edward Jenner and His Smallpox Research
According to the CDC, vaccination with today's smallpox vaccine within three days of infection can prevent or significantly weaken the disease. Vaccination four to seven days after the time of infection "likely" offers some protection against the disease and may weaken the symptoms.
The Smallpox Vaccination Today
Routine smallpox vaccinations are no longer required. In the United States they were stopped in 1972. People who do research with the virus are still advised to get a vaccination, however. Military personnel, health care workers and aid workers may also receive the vaccination.
The remaining viruses are maintained in two labs under highly secure conditions that have been approved by the WHO (World Health Organization). There have been occasional rumors of hidden virus stocks kept in other labs. This seems to be true, at least in the case of forgotten cultures. One such culture was found in a National Institutes of Health facility in 2014.
There are two concerns relating to the continued existence of smallpox viruses: they could accidentally "escape" from a laboratory and they could be used as a biological weapon. Many countries maintain large stocks of smallpox vaccine and have created emergency plans to deal with a smallpox outbreak. Hopefully these plans will never have to be put into action.
- A letter from Lady Mary Montagu describes the process of engrafting, or variolation.
- The Jenner Museum has been established in Edward Jenner's house In Berkeley, Gloucestershire.
- The CDC has a webpage about the smallpox vaccine.
- The Nature website describes the hidden and forgotten stock of the smallpox virus.
© 2013 Linda Crampton