Discovering vaccines
Lesson 5
How vaccines were discovered and developed
Learning outcomes & key terms
- Students will be able to explain how vaccines were discovered
- Students will understand the difference between a vaccination and variolation
- Students will know the scientists who were involved in the discovery of vaccines
- Students will understand how scientific method has progressed over time
Variolation: inoculation into skin of material from the pocks of variola (smallpox)
Vaccination: treatment with a vaccine to produce immunity against a disease
Understanding science
Biological science
Describing how the requirements for life (for example oxygen, nutrients and water) are provided through the coordinated function of body systems – such as the respiratory, circulatory, digestive and nervous systems
Explaining how body systems work together to maintain a functioning body using models, analogies and flow diagrams
Investigating the response of the body to changes as a result of the presence of germs
Science as a human endeavour
Scientific understanding, including models and theories, is contestable and is refined over time through a process of review by the scientific community
Advances in scientific understanding may rely on technological advances and are often linked to scientific discoveries
People use scientific knowledge to evaluate whether they accept claims, explanations or predictions. Advances in science affect people’s lives and generate new career opportunities
Values and needs of contemporary society can influence the focus of scientific research
Science enquiry skills
Formulate questions or hypotheses that can be investigated or tested
Analysing patterns in data can explain relationships between variables and also identify inconsistencies
Meet Prof Ian Frazer, a vaccine inventor
Prof Booy interviews Prof Frazer, the co-inventor of the HPV Vaccine, which is eliminating cervical cancer around the world – first in Australia!
About vaccination
Many diseases that were once killers are now eliminated (locally) or eradicated (globally) due to the impact of vaccines
Until recently, most people in developed countries have not had their daily routines impacted by an outbreak of disease and have taken vaccination for granted
Vaccines
Vaccines may contain a microorganism or virus in a weakened, live or killed state, or proteins or toxins from the outside of the germ. In stimulating the body’s adaptive immunity they help prevent sickness from an infectious disease
Vaccination
Vaccination is the administration of a vaccine to help the immune system develop protection from a disease
When a sufficiently large percentage of a population has been vaccinated, herd immunity results
The effectiveness of vaccination has been widely studied and verified
Vaccination is the most effective method of preventing infectious diseases. Widespread immunity due to vaccination is largely responsible for the worldwide eradication of smallpox and the elimination of diseases such as polio and tetanus from much of the world
Variolation
Variolation or inoculation was the method first used to immunise an individual against smallpox (Variola) with material taken from a patient in the hope that a mild, but protective, infection ensues
The procedure was most commonly carried out by inserting/rubbing powdered smallpox scabs or fluid from pustules into superficial scratches made in the skin
The patient would develop pustules identical to those caused by naturally occurring smallpox, usually producing a less severe disease than naturally acquired smallpox
Eventually, after about two to four weeks, these symptoms would subside, indicating successful recovery and immunity
(Wikipedia)
Case study
Smallpox eradicated from the world
Interest in smallpox started as long ago as 1000 AD when the Chinese started measures to prevent further spread of the disease
They would collect diseased cells from an infected person and then dry them out by carrying the cells in their pocket. They would then scratch a healthy persons arm and put in some dried cells
Skip forward to 1545 and there was an epidemic in India – 8000 children died
The process the Chinese used became known as variolation which became very popular in the early 1700s
In 1721, Lady Mary Montagu had variolation used for her 2 year old daughter, but not everyone agreed with the process of variolation
Variolation was sometimes fatal: two to three percent of those variolated died of smallpox (in contrast to 20-30% who died after contracting smallpox naturally)
Unfortunately those who were variolated could still have enough active disease to infect others (not the best way to defend against disease)
In 1770 real progress was made into the control of Smallpox
Edward Jenner (1749-1823), an English doctor, heard from a milkmaid that she believed herself protected from smallpox because she had caught cowpox from a cow
Cowpox is an uncommon illness in cattle, usually mild, that can be spread from a cow to humans via sores on the cow being milked
During an infection, dairy workers may have pustules on their hands – sufferers can spread the infection to other parts of the body
We know now that the cowpox virus belongs to the orthopoxvirus family. Orthopoxviruses also include the monkeypox virus and the variola virus, which causes smallpox
Whilst Jenner had ideas about how to vaccinate it wasn’t until 1796 that he tested his hypothesis on an 8 year old boy (James Phipps) with great success
This test lead to the vaccine that we have today
To further the story, in 1855 laws were passed to mandate vaccination
By 1980, Frank Fenner presented at the World Heath Assembly that smallpox was eradicated
Leaders of immunology
Edward Jenner
Edward Jenner is known as the ‘father of immunology’ and is famous for his smallpox vaccine
This was the first successful vaccine to ever be developed
Edward Jenner was born on May 17, 1749, in Berkely, Gloucestershire, England – he died of a stroke in 1823
Jenner wasn’t always met with adoring fans
In 1802, a caricature appeared of Jenner treating patients and those around him sprouting cattle- like appendages
Fears emerged about vaccination
During the eradication of smallpox, there always had to be a last patient- Ali Maow Maalin was exposed to the disease on October 12, 1977
Ali came into contact with the disease and developed a fever. When he was first diagnosed he was told he had chickenpox and sent home
When it was finally obvious that he had smallpox he kept it to himself and didn’t go into isolation. He came into contact with 91 people during his illness
The WHO (World Health Organisation) took precautions to stop any rekindling of the disease
They did a massive search and found all 91 people
No-one got ill and two years after watching the area carefully, smallpox was declared gone
Louis Pasteur
Louis Pasteur furthered the vaccine concept through his work in microbiology. His experiments spearheaded the development of live attenuated cholera vaccine and inactivated anthrax vaccine in humans (1897 and 1904, respectively)
At the age of 46, he had a stroke but recovered sufficiently to do some of his best work
For example, in the 1870s, he applied his previous method of immunising chickens against chicken cholera to anthrax, which affected cattle and thereby aroused widespread interest in combating other diseases with the same approach
In May 1881, Pasteur performed a famous public experiment at Pouilly-le-Fort to demonstrate his concept of vaccination, in this case against anthrax
He prepared two groups of 25 sheep, one goat and several cow. The animals of one group were twice injected, with an interval of 15 days, with an anthrax vaccine prepared by Pasteur; a control group was left unvaccinated
Thirty days after the first injection, both groups were injected with a culture of live anthrax bacteria. All the animals in the non-vaccinated group died, while all in the vaccinated group survived
The public reception was jubilant
Class activity
Part 1
- You will work in groups of 3
- You will create a slide on one of the topics below (decided by your teacher)
- Each member of the group try a different summarising method (using the methods that follow) and present the information on one slide
- Find pictures that represent your findings for another slide (method 2)
- The finished slides (2 in total – one info and one graphic) should then be printed off and arranged in order for the class to see
Choose a method to create your slides
Method 1
- Delete unwanted extra (trivial) details that can go without losing the overall sense
- Delete information that is repeated in some way
- Replace the details with more general terms or descriptions
- Select a topic sentence or create 1 if it is missing
- Check there is sufficient detail to make sense
Method 2
- Create a visual representation of key aspects of the information such as a table, chart, flow diagram or spider diagram
- Try to show the relationships between pieces of information where you can
Method 3
- Skimming – preview the information on the factsheet by highlighting the important information
- Then focus on the headings and subheadings to write a short written summary of the factsheet
Topics
1. Variolation – 900-1000
- What is variolation?
- Who discovered and used it in this time period?
- Was it effective?
- What where the dangers with this method?
2. Lady Montagu – 1700’s
- How did Lady Montagu contribute to the adoption of variolation?
- How was this method different to previous variolation methods?
- Was it effective?
3. Edward Jenner – 1796
- Explain how Edward Jenner discovered the smallpox vaccination
- When was smallpox officially eradicated from the world?
- Was it effective?
- What where the dangers with this method?
4. Variolation & vaccination – 1840
- England banned variolation and only vaccination was allowed and provided free for the poor
- What is the difference between variolation and vaccination?
- Why do you think variolation was prohibited in favour of vaccination?
5. Louis Pasteur – 1880 & 1881
- Pasteur developed and publicly demonstrated his anthrax vaccine
- How did he convince his peers that his vaccine worked?
Summary
In this lesson you have learned what vaccines are, the value to society and how they are discovered
Vaccines contain a microorganism in a weakened live or killed state, or the proteins or toxins from the outside of the germ. These stimulate the body’s adaptive immunity to help prevent disease
Vaccination is the administration of a vaccine to help the immune system develop protection
Vaccines are still being invented today by leaders such as Prof Ian Frazer – these modern day leaders build their vaccines on the science first developed by leaders such as Jenner and Pasteur
Quiz
1) Rubbing powdered smallpox scabs into superficial scratches on a well person’s skin is called
a) Vaccination
b) Immunity
c) Boosting
d) Variolation
2) The person credited with inventing the smallpox vaccine is
a) Edward Jenner
b) Louis Pasteur
c) Ian Frazer
d) Walter Orenstein
3) Smallpox was officially declared eradicated in
a) 1770
b) 1980
c) 1977
d) 1721
4) The cholera and anthrax vaccines were developed in the late 19th century by
a) Edward Jenner
b) Louis Pasteur
c) Ian Frazer
d) Walter Orenstein