WHAT IS A VACCINATION?
Before we explain what is a vaccination and
mechanism of it. We must know the general
immune system specially immune response.
The immune response is how your body recognizes
and defends itself against bacteria, viruses, and substances
that appear foreign and harmful.
The immune system protects the body from possibly harmful
substances by recognizing and responding to
Antigens are substances (usually proteins) on the
surface of cells, viruses, fungi, or bacteria.
Nonliving substances such as , chemicals, drugs,
and foreign particles (such as a splinter) can also
The immune system recognizes and destroys, or
tries to destroy, substances that contain antigens.
The immune system includes specialized white
blood cells, called lymphocytes that adapt
themselves to fight specific foreign invaders.
,These cells develop into two groups in the bone
From the bone marrow, one group of lymphocytes
migrates to a gland called the thymus and become
T lymphocytes or T cells.
, Within the thymus, the T cells mature under the
influence of several hormones.
The T cells mature into several different types,
including helper, killer and suppressor cells.
T cells are responsible for cell-mediated immunity.
This type of immunity becomes deficient in persons
with HIV, the virus that causes AIDS, because HIV
attacks and destroys helper T cells.
The other group of lymphocytes, B lymphocytes or
B cells, mature and develop within the bone marrow
In that process, they achieve the ability to recognize
specific foreign invaders. From the bone marrow, B
cells migrate through the body fluids to the lymph
nodes, spleen and blood.
B lymphocytes provide the body with humeral
immunity as they circulate in the fluids in search of
specific foreign invaders to destroy.
Administration of substance to a person with the
purpose of preventing a disease
Traditionally composed of a killed or weakened
Vaccination works by creating a type of immune
that enables the memory cells to later respond to a
similar organism before it can cause disease
Vaccines are used to boost your immune system and
prevent serious, life-threatening diseases.
HOW VACCINES WORK
Vaccines "teach" your body how to defend itself when
germs, such as viruses or bacteria, invade it:
They expose you to a very small, very safe amount of
viruses or bacteria that have been weakened or killed.
Your immune system then learns to recognize and
attack the infection if you are exposed to it later in life.
As a result, you will not become ill, or you may have a
milder infection. This is a natural way to deal with
Ability to elicit the appropriate immune response for the
Long term protection.
Safety: the vaccine it self should not cause disease.
Stability: should retain immunogenicity , despite adverse
storage conditions prior to administration.
TYPES OF VIRAL VACCINATION
MODIFIED LIVE VIRUS VACCINE:
- Prepared from either virulent virus or attenuated
mutant selected for their relative a virulence or less
-they are capable to multiply in the host , to amplify
the amount of antigen and cause subclinical
infection to elect immune response similar to that
occurring after natural vaccine .
A-LIVE VIRULENT VIRUS :
virulent virus given by unnatural route or to non
susceptible old animals.
Virulent ILT virus given in the cloacal mucous
CPD virus into the skin of lambs .
non susceptible old animals
Also may given to non susceptible old
animals to protect new born by maternal
immunity . EX: avian encephalomyelitis .
these vaccine must be given to all
susceptible animal to avoid shedding of
prepared from naturally occurring virus of low
Homologous vaccine as : New castle disease
Heterologous vaccine as : pigeon poxvirus is
used agonist fowl pox virus .
ATTENUATED VACCINE IS USUALLY ACHIEVED BY
PASSAGE OF THE VIRUS IN FOREIGN:HOST
Embryonated egg .
Tissue culture cells .
RNA virus selected that have a better ability to grow
in the foreign host , is higher virulence.
EX: - render pest virus in rabbit .
- Rabies virus in avian embryo .
ADVANTAGE OF ATTENUATED VACCINE :
1. they activated all phases of immune system elicit humeral
IgG and local IgA.
2. they raise an immune response to all protective antigen .
3. they give quick immunity in majority of vaccine
4. in case of polio and adenovirus vaccine administration is easily
5. easily transported in the field .
6. can lead to elimination of wild tripe virus from the community .
7. low cost to produce .
consist of viruses generally cultivated tissue
culture or embryonated eggs and chemically
inactivated by formalin or beta propio lactone .
killed virus vaccine generally required more
than one dose to induce immunity and periodic
booster doses to maintain immunity
-in activated vaccine often induce an immunity
that is less protective and of a shorter duration
than that induced by modified live vaccine.
ADVANTAGE OF INACTIVATED VACCINE :
1. they don't revert to virulence .
2. they are safe use in pregnant and immune
3. they give sufficient humeral immunity if
boosters given .
4. there is no mutation .
5. They can be used with immune deficient
DISADVANTAGE OF INACTIVATED VACCINE :
1. Some vaccine don't raise immunity .
2. Boosters tend to be needed .
3. Low stimulant of local immunity IgA.
4. High cost .
IMMUNO POTENTIATION OF INACTIVATED
immunogenicity of inactivated vaccine , subunit or
peptide vaccine can be enhanced by mixing then
-incorporation into liposome .
-immune stimulating complex .
1. For a few weeks after birth, babies have some protection
from germs that cause diseases. This protection is passed
from their mother through the placenta before birth. After a
short period, this natural protection goes away.
WHY WE NEED VACCINES:
2. Vaccines help protect against many diseases that used
to be much more common.
Examples include: tetanus, diphtheria, mumps, measles,
pertussis (whooping cough), meningitis, and polio.
Many of these infections can cause serious or life-
threatening illnesses and may lead to lifelong health
Because of vaccines, many of these illnesses are now
Immunization is defined as the procedure by which
the body is prepared to fight against a specific
disease . it is used to induce the immune resistance
of the body to specific disease. Immunization is of
two types :
2. active immunization.
Passive immunization or immunity is produced
without challenging the immune system of the body
It is done by administration of serum or gamma
globulins from a person who is already immunized
(affected by the disease) to a non-immune person .
Passive immunization is acquired either naturally or
Is acquired form the mother before and after birth.
Before birth, Immunity is transferred from mother to
the fetus in the form of maternal antibodies (mainly
IgG) through placenta .
After birth, the antibody(IgA) are transferred
through breast milk
PASSIVE ARTIFICIAL IMMUNIZATION
It developed by injecting previously prepared
antibodies using serum from humans or animals.
This type of immunity is useful for providing
immediate protection against acute infection like
tetanus, measles ..
Active immunization or immunity is acquired by
activating immune system of the body . Body
develops resistance against disease by producing
antibodies following the exposure to antigens.
Active immunity is acquired either naturally or
Active natural immunization
Naturally acquired active immunity involves activation of
immune system in the body to produce anti bodies . It is
achieved in both clinical and subclinical infections.
Active artificial immunization
is a type of immunization that achieved by the administration of
vaccines or toxoids.
HOW TO QUANTIFY IT AND HOW TO USE IT TO
In comparison to unvaccinated individuals, vaccinated
individuals have fewer clinical symptoms, reduced
susceptibility and reduced infectivity. The first two effects
of vaccination can mean that each vaccinated individual
is protected against clinical symptoms
From experiments and field trials, the extent of
individual protection can be determined by a
statistical analysis of the resulting data.
In addition, there is an effect of the vaccination on
the populations in which one or more individuals
This effect on the population is due to the effects of
vaccination on susceptibility and infectivity of the
Such an application of herd immunity is especially
important in protecting farm animals.
To plan and evaluate vaccination at the population
level, the herd immunity needs to be quantified.
It will be illustrated that it is possible, not only
theoretically but also practically, to quantify herd
immunity among farm animals with data from small-
scale experiments as well as with data from field
THE DIFFERENCE BETWEEN VACCINATION AND
vaccination: like influenza vaccines prevent or
mitigate infections ; induce protective immune
response in the body against the viruses
represented in the vaccine and also induction of
a specific immunological memory against the
viruses; can be given long before exposure to
the virus and can provide protection over along
period of time.
antiviral: are drug that can treat people who
have already been infected by a virus......the
antiviral drug is effective when administered
within a certain time frame before or after
exposure and is effective during the time that
the drug us being administered.......;do not
destroy their target pathogen; instead they
inhibit their development.
ANTIVIRAL DRUGS HAS TWO LARGE CATEGORIES
1-nucleoside inhibitors; available antiviral
drugs affect viral nucleic acid polymerases.
Viruses targetType of analogNucleosides
Herpes virusesAdenine with
Non-nucleoside inhibitors Antiviral therapy as
interferon: - .inhibit the viral protein synthesis.
exogenous interferon is not practiced widely
human Alfa interferon is available as DNA
recombinant and has been used orally treat cats
infected with feline leukemia virus.
other drug inhibit viral mRNA translation are
fomivesin is an antisense DNA that blocks
replication of cytomegalovirus.
Methisazone is specific for poxvirus mRNA
Most of antiviral drug now available are designed to
help deal with HIV ,herpes viruses , the hepatitis B
and C virus and influenza A and B
the major difficulty in developing vaccines and
antiviral vaccine is due to viral variation.
CHICKEN POX VACCINE.
Causative M.O: (VZV)varicella_zoster virus.
Signs: a blister-like rush, itching ,tiredness
,loss of appetites and fever.
A health care provider if the person:
1. has a chronic skin or lung disorder.
2. has a weaken immune system.
3. is pregnant
4. has a fever above 102.
5. has bacterial infection.
TWO DOSES OF THE VACCINE
Two doses of the vaccine are about 90%
effective at preventing chickenpox.
When you get vaccinated, you protect yourself
and others in your community.
Children who have never had chickenpox
should get 2 doses of chickenpox vaccine at
1st Dose: 12-15 months of age
2nd Dose: 4-6 years of age (may be given
earlier, if at least 3 months after the 1st dose).
People 13 years of age and older (who have
never had chickenpox or received chickenpox
vaccine) should get two doses at least 28 days
WHAT ARE THE RISKS FROM CHICKENPOX
A vaccine, like any medicine, is capable of causing
serious problems, such as severe allergic reactions,
Pneumonia (very rare),Seizure and mild problem
such as(swelling-fever-mild rash).
Getting chickenpox vaccine is much safer than
getting chickenpox disease. Most people who get
chickenpox vaccine do not have any problems with
Reactions are usually more likely after the first
dose than after the second.
Some people who are vaccinated against
chickenpox may still get the disease. However,
it is usually milder with fewer blisters and little
or no fever.