Vaccination / Immunisation
Objectives
1. Briefly explain how vaccines work.
2. Give a brief overview of the history of vaccines.
3. Give a brief overview of the controversies surrounding Pertussis and MMR
vaccines.
4. Briefly explain what is meant by the primary and secondary immune response.
5. Compare and contrast natural active, natural passive, artificial active and
artificial passive immunity.
Vaccination ………………………………………………………………….
Immunity develops in response to the administration of either dead or living (but
artificially weakened) microbes (vaccines) or deactivated toxins (toxoids). The
vaccines and toxoids retain the antigenic properties that produce immunity but should
not cause the disease.
The material administrated may be a
…………………….
………………….… form of the pathogen.
Smallpox was the first disease people tried to prevent by inoculating
themselves with other types of infections.
Smallpox inoculation was started in China (or India) before 200 BC.
In 1796 Edward Jenner inoculated using cowpox (a mild relative of the
deadly smallpox virus). The word vaccination was first used by Edward
Jenner.
Vaccination (Latin: vacca = cow) is so named because the first vaccine
was derived from a virus affecting cows—the relatively benign cowpox
virus—which provides a degree of immunity to smallpox.
Vaccination Initiatives
An 1853 law required universal vaccination against smallpox
in England and Wales, with fines levied on people who did
not comply.
Many modern vaccination policies allow exemptions for
people with:
compromised immune systems,
allergies to the components used in vaccinations, or
strongly-held objections.
Vaccines have contributed to the eradication of
smallpox. Other diseases such as rubella, polio,
measles, mumps etc, chickenpox, and not as common
as they were a hundred years ago.
As long as the vast majority of people are vaccinated,
it is much more difficult for an outbreak of disease to
occur, let alone spread. This effect is called
Objections!!
Vaccination policies may be met with resistance
from some groups and individuals in society. Why
may people object to vaccination policies?
(Medical opinion is that the benefits of preventing suffering and death from infectious diseases greatly
outweigh the risks of adverse effects following immunization)
PERTUSSIS
‘A 1974 report ascribed 36 reactions to whooping cough (pertussis) vaccine, a
prominent public-health academic claimed that the vaccine was only marginally
effective and questioned whether its benefits outweigh its risks, and extended
television and press coverage caused a scare. Vaccine uptake in the UK decreased
from 81% to 31% and pertussis epidemics followed, leading to deaths of some
children. Mainstream medical opinion continued to support the effectiveness and
safety of the vaccine; public confidence was restored after the publication of a
national reassessment of vaccine efficacy.
MMR vaccine
In the UK, the MMR vaccine was the subject of controversy after publication of a
1998 paper by Andrew Wakefield, et al., reporting a study of 12 children mostly with
autism spectrum disorders with onset soon after administration of the vaccine.
Wakefield suggested that giving children the vaccines in three separate doses would
be safer than a single vaccination. This suggestion was not supported by the paper,
and several subsequent peer-reviewed studies have failed to show any association
between the vaccine and autism.
Primary and Secondary Immune Response
Primary response
First exposure to pathogen, immune response
……………………………………………….
Latent period of 5-10 days before measurable
amounts of specific antibodies appear in blood.
Secondary response
Subsequent exposure to same antigen.
Antibody production is ……………………….
Maximum antibody concentration reached in < 2
hrs.
Case 1
Helen is 26 and has just started her nursing
degree. She has been advised that she will
need a course of Hepatitis B vaccinations. She
is not very happy about this as she believes
that vaccinations may have adverse effects on
health and well being and anyway, she is fit
and healthy, and should not have to worry
about picking up infections from patients.
How might she be at risk of Hepatitis B infection?
Is the onset of Hepatitis B infection rapid or insidious?
Is she right in thinking that her youth and health will protect her?
What is the general aim of immunisation?
How would you explain to Helen how vaccines work?
Can she refuse to have the injections?
Why are 3 injections necessary?
What sort of immunity is this?
a) Natural active
b) Natural passive
c) Artificial active
d) Artificial passive
Is the immunity in this case long or short term?
Case 2
Craig is 5 years old and has just started
school. He has developed a rash with
obvious vesicles (small blisters), his
temperature is 380C and he is generally
unwell and a bit irritable. His mother
reports that he has had all his
necessary immunisations.
What organism is likely to have caused his condition?
a) Varicella (Chicken Pox)
b) Rubella (German Measles)
c) Rubeola (Measles)
d) Small pox
How is this organism transmitted?
Where is he most likely to have picked up the infection?
Why are antibiotics an ineffective treatment option?
Does the fever (pyrexia) have any useful function in this case?
Why then are anti-pyretics a good idea?
Will he be able to get this infection again?
What sort of immunity is conferred by getting the disease?
a) Natural active
b) Natural passive
c) Artificial active
d) Artificial passive
Is the immunity in this case long or short term?
Case 3
Megan was born 7 days ago via a normal
delivery. Her 17 year old mother, Zoe, has
been breast feeding since the birth, but is
finding it very uncomfortable In addition,
the baby seems to want to feed every 2
hours and Zoe thinks that her baby is not
getting enough milk. She wants to
discontinue breast feeding.
What advice would you give Zoe regarding the benefits of breast feeding?
How else does the baby receive maternal antibodies?
What sort of immunity is Megan being given by Zoe?
a) Natural active
b) Natural passive
c) Artificial active
d) Artificial passive
Is the immunity in this case long or short term?
Victor (aged 82) cut his hand whilst doing some
Case 4
gardening. He wiped the wound with a wet tissue and
applied a dressing and bandage himself at home. He
thought this was sufficient, but when his granddaughter
visited him two days later, she insisted on taking him to
A and E. He admitted he couldn’t remember the last time
he had a tetanus injection, but he thinks it was more than
20 years ago (he doesn’t like going to the GP). The
wound is quite deep and looks dirty (it is still
contaminated with soil) and is looking a bit inflamed.
What spore forming organism from the list below might have contaminated his
wound?
a) Clostridium tetani
b) Salmonella
c) Chlamydia
d) E.Coli
How is this organism transmitted?
Which muscles are particularly affected by this organism?
Why might he need an injection of Tetanus immune globulin rather than
Tetanus vaccine?
What sort of immunity is this?
a) Natural active
b) Natural passive
c) Artificial active
d) Artificial passive
Is the immunity in this case long or short term?
MCQ’s
In 3 hours single bacterium that divides every 20 minutes will produce:a) 9 offspring
b) 32 offspring
c) 512 offspring
d) 1024 offspring
The term for ‘hospital acquired’ (from another patient, staff or environment) is:a) Nosocomial
b) Pathogenic
c) Resident
d) Transient
Organisms that will cause disease are known as:a) Nosocomial
b) Pathogenic
c) Resident
d) Transient
The treatment which achieves only killing of non-sporing or vegetative microorganisms is:a) Disinfection
b) Autoclaving
c) Sterilization
d) Irradiation
A treatment which achieves the complete killing or removal of all types of microorganisms, including spores is:a) Hand washing
b) Sterilization
c) Disinfection
d) Irrigation
Active immunity
Passive immunity