A powerpoint covering the vaccination section of edexcels biology B3.

1. Vaccinations
RevisionEdexcel

2. Edward Jenner
• Edward Jenner is an English scientist that lived in
the 18th century.
• His works and findings include finding the cure
for smallpox and creating a vaccine.
• He discovered that milkmaids did not contract
smallpox, however they did contract cowpox
much less serious condition.
• Jenner concluded that the pus from the blisters
on the milkmaids hands, caused by
cowpox, prevented the milkmaids from
contracting smallpox

3. • He inoculated (infected on purpose) a small
boy, by infecting his arms with the pus from the
cowpox, causing the boy to become infected.
• After a short fever, the boy returned to normal
health.
• Jenner then realised the boy could not contract
smallpox, or the cowpox virus again.

4. Immunisation
• This is the process in which a person’s body
becomes resistant to an infection from a
pathogen.
• Passive immunisation is provided by antibodies
from outside the body, such as through breast
milk or an injection.
• Active immunisation is more common and is the
result of normal infection by a pathogen or by an
injection.

5. Vaccination
• The steps of vaccination are;
1. Isolating the weakened version of a
pathogen, and then infecting an individual with
it, normally in the form of an injection.
2. The individuals immune response then begins.
On the cell wall of the pathogen are antigens.
These are often proteins, which white blood
cells recognise as foreign (lymphocytes)
3. Lymphocytes then produce antibodies to
destroy the pathogens.

6. • The first time a person is infected by a
pathogen, the body responds slowly to it, causing
the infected person to be ill for a while. It takes
time for the lymphocytes to produce antibodies.
• However, if you have had the illness before, and
your memory lymphocytes are able to
remember the antigen, they can quickly produce
antibodies more quickly, meaning we do not get
the disease for the second time.
• This is the case for the cold virus. Each time you
get a cold, you do not get the same cold you have
had before, but a slightly different one.

7. Advantages and disadvantages
• There are both risks and advantages associated
with vaccinations.
• An advantage is that they can prevent many
people from becoming infected by pathogens.
• The more people that are vaccinated, the less
likely it is that anybody will catch the disease, this
is called herd immunity.
• A small risk associated is a negative reaction to
the vaccination, causing some people to feel ill
after having the vaccine.

8. • Some people have weakened immune systems
(such as people with HIV/AIDS), and have to be
careful when receiving a vaccine.
• In the past there has been controversy
surrounding vaccines, such as the MMR vaccine
(measles, mumps and rubella). Some people
suggested there was a link between the vaccine
and autism, causing the number of children being
vaccinated to go down. It was later discovered
that there was no link between the two, but
some parents still do not trust the vaccine.