Transcript Vaccinations - Science with Glee

Vaccinations
Starter
1.
2.
What are the two ways that white blood
cells fight infection?
How do we acquire immunity?
Lesson objectives
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To be able to explain how vaccination works (C )
To be able to understand the historical
development of vaccination (C )
To understand herd immunity (C )
To be able to weigh up some of the pros and
cons of vaccinations (B-A* )
To understand the problems in developing
vaccinations against influenza and HIV (B-A*)
Now…
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Brainstormwhat do you already know about
vaccinations?
What vaccinations have you had?
Why are vaccinations important?
What do you think this 1802 cartoon refers to?
Eradicating smallpox
Smallpox used to be one of the deadliest of
infectious diseases.
Caused by virus- airbourne transmission and
through contact with an infected person.
Causes pustules to rise on the skin and eyes,
eventually covering the body and high fever.
Between 20 and 60 percent of all people infected,
and up to 80 percent of all children infected,
died of smallpox. Those who survived were
often disfigured or blind.
What was done to fight smallpox?
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Variolation—the deliberate infection with smallpox was a technique
that developed in Asia and spread to the west by the 1700’s
Smallpox scabs were blown into the nose or added to a cut in the
skin who then contracted a mild form of the disease. Upon recovery,
the individual was immune to smallpox.
Between 1% to 2% of those variolated died as compared to 30%
who died when they contracted the disease naturally.
Inoculation used a less virulent strain of smallpox, which made it
safer than catching smallpox during an outbreak.
Who developed vaccinations?
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Vaccinations were developed by Edward Jenner in 1796
http://www.bbc.co.uk/learningzone/clips/edward-jennerthe-discovery-of-smallpox-vaccine/2456.html
How did Edward Jenner develop vaccination?
Explain his discovery- Either in a paragraph, flowchart or cartoon strip.
Jenner saw
a problem
that people
were dying
of
smallpox.
Jenner
made some
cuts on
James’ arm
and put
Sarah’s pus
in to it.
James did not
get
smallpox.
James recovered
from cowpox.
James got cowpox
and was ill for a few
days.
Jenner decided
that his
hypothesis had
been correct –
cowpox had
provided
protection from
cowpox.
Jenner then
collected some pus
from a smallpox
victim.
Jenner noticed that
milkmaids who got cowpox
didn’t seem to get
smallpox.
Jenner decided to test his
ideas out by doing an
investigation
Jenner
collected
some pus
from a cowpox
spot from
Sarah the
milkmaid.
Jenner put the
smallpox pus into
James’ arm.
Jenner chose a
young boy who had
not had either
disease. He was
called James
Phipps.
Jenner formed a hypothesis
(idea) that cowpox provided
some protection against
smallpox.
What do vaccines contain?
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Vaccination involves putting a small
amount of an inactive form of a pathogen
(disease causing micro-organism) into the
body. Vaccines can contain:
live pathogens treated to make them
harmless
harmless fragments of the pathogen
toxins produced by pathogens
dead pathogens
How do they work?
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These all act as antigens. When injected into
the body, they stimulate white blood cells to
produce antibodies to fight the pathogen.
The vaccine contains only a weakened or
harmless version of a pathogen, which means
that the vaccinated person is in no danger of
developing the disease. Some people, however,
may suffer a mild reaction. If the person later
becomes infected with the pathogen, the
required lymphocytes are able to reproduce
rapidly and destroy it.
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http://www.abpischools.org.uk/page/mod
ules/infectiousdiseases_immunity/immunit
y6.cfm
Put the sentences in the correct order
Herd immunity
What is herd immunity?
For a vaccination programme to be successful, it
depends on herd immunity. If the majority of
a population is vaccinated, not only are those
people kept safe, but viruses cannot spread
between immunised people. The immunised
people provide a barrier that stops the infection
from spreading to others in the group. If only a
few people are vaccinated, this will help them
avoid infection, but it will not protect the group.
Based on this should people be forced to have
vaccinations?
Are vaccinations safe?
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Vaccinations can never be completely safe
because side-effect levels vary. So, when making
a decision, these are some of the factors that
should be considered:
When fewer people are vaccinated, the
number of cases of the disease increases.
The chance of falling seriously ill or dying
from the disease may be far greater than
the chance of experiencing a serious sideeffect.
Using a vaccine may be much cheaper
than treating a very ill person.