A doctor performing typhoid vaccination, 1943.
1
HOST DEFENSES
(IMMUNITY)
By
DR Mohammad Ayaz
MBBS, MPH, MSc
Associate Professor &
Head Of Dept, Community Medicine
LEARNING OBJECTIVES
1.
Describe the EPI Program.
2.
Enlist various vaccines used in EPI.
3.
Explain Cold Chain and its importance.
Today’s Situation

10.5 million infant and childhood deaths
each year in the developing world

70% are due to five conditions:
pneumonia, diarrhea, measles, malaria,
and malnutrition.

At least 3/4 of all childhood illness
episodes are caused by one of these
conditions
4
•4 million neonatal deaths
annually.
•Two thirds of neonatal mortality occur
in the first week of life, of these two
thirds die within the first 24 hours of
life
5
Immunization
Quality
and Safety
Providing an ineffective
vaccine is worse than
providing no vaccine at all.
6
Immunization

Vaccine potency
• Proper vaccine handling
• Proper conditions and
• Use of Vaccine Vial Monitors
• Safe injection practices
•
•
•
•
•
Clean work space
Hand washing
Sterile needle and syringe for each injection
Assuring sterile vaccines and diluents.
Appropriate sharps and waste collection and
disposal
7
Vaccine-PREVENTABLE Diseases
Anthrax
Cervical Cancer
Diphtheria
Hepatitis A
Hepatitis B
Haemophilus influenzae type b (Hib)
Human Papillomavirus (HPV)
Influenza (Flu)
Japanese Encephalitis (JE)
Lyme Disease
Measles
Meningococcal
Monkeypox
Mumps
Pertussis (Whooping Cough)
Pneumococcal
Poliomyelitis (Polio)
Rabies
Rotavirus
Rubella (German Measles)
Shingles (Herpes Zoster)
Smallpox
Tetanus (Lockjaw)
Tuberculosis
Typhoid Fever
Varicella (Chickenpox)
Yellow Fever
8
Definition

Immunization (vaccination) is a way to trigger your
immune system and prevent serious, life-threatening
diseases.

Vaccination is the administration of antigenic
material (the Vaccine) to produce immunity to a
disease. Vaccines can prevent or ameliorate the
effects of infection by a pathogen.
9
Vaccination

Vaccination (Latin: vacca—cow) is so
named because the first vaccine was
derived from a virus affecting cows, which
provides a degree of immunity to
smallpox.
10
Expanded Programme Of
Immunization (EPI)

The Global program of immunization
was launched following a resolution
of world health Assembly in 1974
11
Expanded Programme
for Immunization
The EPI in Pakistan was initiated as a pilot project in 1976.
Was launched at federal level in 1978.
Was
Established nation-wide by 1981.
The
programme currently targets seven vaccine preventable diseases
i.e.
Without effective
immunization,

it is estimated that 100,00 deaths
due to measles, 70,000 cases of
neonatal tetanus and 20,000
paralytic cases of poliomyelitis would
occur in Pakistan each year.
13
The routine immunization schedule



targets one dose of BCG,
3 doses OPV and DPT vaccines
and one dose of measles vaccine in the first year
of life.

At birth dose of OPV is scheduled if there is
health staff contact with the infant before it
reaches 6 weeks age.
14
Immunization
Immunization Schedule for Infants:
Recommended by WHO - Expanded Program on Immunization
Age
Birth
6 weeks
10 weeks
14 weeks
9 months
Vaccines
BCG, OPV0
DPT 1, OPV 1
DPT 2, OPV 2
DPT 3, OPV 3
Measles –
15
Immunization Schedule for Infants:
Recommended by WHO - Expanded Program on Immunization
.
AGE
Vaccines to be given
Route of
administration
At Birth
BCG, OPV
Intra dermal, oral
At 6 Weeks
DPT 1
OPV 1
HBV-1
Intra muscular
Oral
At 10 Weeks
DPT 11
OPV 11
HBV-11
Intra muscular
Oral
At 14 Weeks
DPT 111
OPV 111
HBV-111
Intra muscular
Oral
At 9 Months
Measles
Sub Cutaneous
20-23 Months
DPT
OPV
Intra Muscular
Oral
16
.
Tetanus
Toxoid
TT1
TT2
TT3
TT4
TT5
IntraMuscular
At first
contact or
as early as
possible
during
pregnancy
4 weeks
after TT1
6-12
Months
after TT2
At least 1
Year after
TT3
At least 1
Year after
TT4
17
CONTRA-INDICATIONS
General Contraindications

Any acute illness

Severe malnutrition.

In known cases of immune deficiency.
RELATED TO GROUPS OF VACCINES

During pregnancy there is mild to fatal damage to the foetus.

The continuous administration of glucocorticoid usually prednisolone
impairs the body response to a primary antigenic stimulation but the
secondary response is not appreciably affected.

Total body exposure to ionizing radiation.

Administration of anti-metabolites such as 6-M.P. or azothioprine, nitrogen
mustard, actinomycin, as they inhibit the primary response.
18
INDIVIDUAL VACCINES

BCG

Whooping cough- the appearance of any neurological
is contraindicated in extensive dermatosis.
symptoms after the first or second dose is an absolute
contraindication.

Toxoids- No contraindication for TT.

For Polio Vaccine Diarrhea, No polio vaccine to be
administered within three weeks of tonsillectomy.

Measles- History of febrile convulsions and active
tuberculosis.
19

Smallpox was the first disease people tried to
prevent by inoculating themselves.

Smallpox inoculation was started in India
and China before 200 BC.

In 1718, Lady Mary Wortley Montague
reported that the Turks have a habit of
deliberately inoculating themselves with fluid
taken from mild cases of smallpox and she
inoculated her own children.

In 1796 Edward Jenner inoculated using
cowpox (a mild relative of the deadly smallpox
virus).

The term vaccination was first used by Edward
Jenner in 1796.

Louis Pasteur further adapted in his pioneering work
in microbiology.
20

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' and 'immunization' generally have the
same meaning.

This distinguishes it from inoculation which uses
unweakened live pathogens, although in common
usage either is used to refer to an immunization.

The word "vaccination" was originally used
specifically to describe the injection of smallpox
vaccine.
21
Jenner's handwritten draft of the first vaccination.
22
Mary Wortley Montagu, 1716.
23
USES OF IMMUNOLOGY
For the immunization programs.
In hypersensitivity and drug
reaction.
Forecasting of epidemics.
Serological diagnosis and blood
grouping.
Carrier detection.
Organ transplantation.
Four different types of vaccines
are currently available.

Attenuated (weakened) live virus is used in the measles,

Killed (inactivated) viruses or bacteria are used in some

Toxoid vaccines, such as the diphtheria or tetanus vaccines,

Biosynthetic vaccines contain human-made substances that the
mumps, and rubella (MMR) vaccine and the varicella (chicken pox)
vaccine. These vaccines may cause serious infections in people with
weakened immune systems.
vaccines, such as the influenza vaccine. These vaccines are safe, even
in people with weakened immune systems.
contain a toxin or chemical made by the bacteria or virus. They make
you immune to the harmful effects of the infection rather than the
infection itself.
immune system thinks are infectious organisms. The Hib
(Haemophilus influenzae type B) conjugate vaccine is one example.
25
Immune System
26
BARRIERS AND INNATE
IMMUNITY

Immune system includes barriers These barriers are

innate immunity (with you from birth) skin, stomach
acid, mucus (which traps bacteria and small particles),
the cough reflex, and enzymes in tears and skin oils. If
an antigen gets passed the external barriers, it is
attacked and destroyed by other parts of the immune
system.
27
BARRIERS AND INNATE
IMMUNITY continued

BLOOD COMPONENTS
The immune system includes certain types of white blood cells. It also
includes chemicals and proteins in the blood, such as complement
proteins and interferon. Some of these directly attack foreign substances
in the body, and others work together to help the immune system cells.

INFLAMMATION
The inflammatory response (inflammation) occurs when tissues are
injured by bacteria, trauma, toxins, heat, or any other cause. Chemicals
including histamine, bradykinin, serotonin, and others are released by
damaged tissue. These chemicals cause blood vessels to leak fluid into
the tissues, causing swelling. This helps isolate the foreign substance
from further contact with body tissues.
28
ANTIGEN:
“An antigen is a substance which when introduced into the body
stimulates specific immune response”.
Chemically an antigen may be a
protein,carbohydrate,lipid or
nucleic acid and usually foreign or nonself to the body.
ANTIBODY:
“An antibody is a protein substance produced in response to a
specific antigen with which it combines chemically”.
This reaction of antibody results in neutralization and elimination of
antigen.
IMMUNITY
“Reaction of the body towards any foreign
substance or non self”.
The
immune response is how your body recognizes and defends itself
against bacteria, viruses, and substances that appear foreign and harmful to
the body
Immune
mechanism reacts with every foreign substance whether visible or
microscopic.
Host defense(Immunity) may be
Natural Immunity
Acquired Immunity
IMMUNITY
INNATE
IMMUNITY
Acquired
Immunity
Active
Acquired
Natural
Active Acquired
Artificial
Active Acquired
Passive
Acquired
31
Conti
A-Natural Immunity:



It is the resistance offered by
the body under the normal conditions without any
external stimulation.
This is possessed by birth.
It may be species immunity eg Rats mice and dog
against tuberculosis.
Racial immunity, Negro's to yellow fever.
B-Acquired Immunity:The immunity which is
acquired by natural or artificial means and may be
active or passive.
1.
ACTIVE IMMUNITY

It is the immunity which when one individual
develops as a result of infection or by specific
immunization.
Acquired Immunity
Naturally Acquired Immunity
• Immunity from infection: “Naturally acquired active
immunity”. Often lifetime or long-lasting.


• Immunity from mother to fetus via transplacental transfer or
colostrom results in “Naturally acquired passive immunity”.
Short-lived, e.g. 6 months.
– Artificially Acquired Immunity
 • First performed for smallpox by Edward Jenner
• Immunity from vaccine: Artificially acquired active immunity

• Artificially acquired passive immunity acquired by injection of
humoral antibodies: short term immunity. Serum ”Antiserum”
33
IMMUNITY Conti
Active immunity depends upon the Humoral and
cellular responses of the host.
HUMORAL RESPONSE: Comes from the B lymphocytes and
manufactures specific antibodies. The antibodies are localized in the
immunoglobulin of serum.
Immunoglobulins
CELLULAR
Infectious
are divided into 5 main classes IgG, IgM,IgA,IgD and IgE.
RESPONSE: Is achieved by the T lymphocytes.
disease like M.TB, M.Leprae, S.typhi, Candida albicans
and many viruses escape from the Humoral response.Cellular
immunity provides protection against such diseases.
IMMUNITY Conti
Active Immunity may be acquired in three ways
•Following
measles).
clinical infections (chickenpox, rubella and
•Sub-clinical
diphtheria).
•Following
or in-apparent infection(Polio and
Immunization (Live or killed vaccine).
IMMUNITY Continued
2. PASSIVE IMMUNITY: When antibodies produced
in one body are transferred to another to induce
protection against disease.
•
Passive immunity may be induced
I.
By administration of an antibody containing
preparation(antisera,immune globulin)
II.
By transfer of maternal antibodies across the
placenta.
III.
By transfer of lymphocytes.
PASSIVE IMMUNITY Continued:
Passive immunity differs from active
immunity as
a)
b)
c)
d)
Immunity develops rapidly.
Immunity produced is temporary.
There is no education of the reticulo-endothelial
system.
Passive immunization is useful for individuals who
cannot form antibodies or take time to develop
antibodies following active immunization.
HERD IMMUNITY
“It is the level of resistance of a community or group of people to a
particular disease”.



Herd immunity implies group protection beyond that afforded by
the protection of immunized individuals.
An epidemic declines before the whole population becomes
immune.
If two third population in a community becomes immune, the
remaining one third become immune.
The elements which contribute to herd immunity are
a)
Occurrence of clinical and sub clinical infection in the herd
b)
Immunization of the herd.
c)
Herd structure ( Birth, death and population mobility).
IMMUNE RESPONSE
A. PRIMARY IMMUNE RESPONSE:
When
After
an antigen is administered for the first time.
3-10 days antibodies appear in the blood.
The
first antibody is IgM which rises steadily for 2-3
days reaches to peak and then declines as fast as it
developed.
If
the antigenic stimulus was sufficient IgG antibody
appears in a few days
IgG reaches to peak in7-10 days and falls over a period
of weeks or months.
IMMUNE RESPONSE continued
Secondary (BOOSTER) RESPONSE:
Secondary response is different from the
primary response in a number of ways
Shorter
latent period.
Production of antibody more rapid.
Antibody more abundant.
Antibody response maintained at higher levels for a
longer period.
The antibody have greater capacity to bind the antigen.
41

.
42
Humoral (Antibody-Mediated) Immunity

– Humoral system responds to extra-cellular foreign invaders.

– The humoral immune system involves antibodies produced
by “plasma cells” via B cells (B-lymphocytes) in response to a
specific antigen.

B Cells interact with invader via their receptor sites and
differentiate into plasma cells which produce antibodies.

Some B cells become “memory cells” which produce the
“secondary response”.

– Antibodies primarily defend against bacteria, viruses, and toxins
in blood plasma and lymph.
43
Cell-Mediated Immunity
(Continued)

•–
The cell-mediated immune system makes use of T
cells (T-lymphocytes) and does not involve antibody production.
Response involves “T” cells
• T- Cytotoxic cells
• T- Helper cells

T cells do not interact with invader but destroys cells infected by
invader by recognizing “foreign” abnormal proteins - not “self”.

Cellular immunity responds primarily to intracellular viruses,
multicellular parasites, tissue transplants, and cancer cells.
44
Protective Outcomes of Antigen-Antibody
Binding
1.
Neutralization of foreign substance or invader
2. Immobilization and prevention of adherence to host
cells.
3. Agglutination and precipitation assisting phagocytosis.
4. Opsonization - facilitates phagocytosis.
5. Activation of complement.
6. Antibody-Dependent Cellular Cytotoxicity (ADCC).
IMMUNIZING AGENTS
The immunizing agents may be classified as
Vaccines.
Immunoglobulins.
Antisera.
VACCINES
Vaccine is an immuno-biological substance
designed to produce specific protection
against a given disease.
It stimulates the production of protective
antibody and other immune mechanisms.
VACCINES Conti
Vaccine may be prepared from
Live
modified organisms
Inactivated
Extracted
Toxoids
More
or killed organisms
cellular fractions
or combinations of these.
recent preparations are sub-unit vaccines
and recombinant vaccines.
LIVE VACCINES

( BCG, Measles, Oral polio) are prepared from live
attenuated organisms.

These organisms are passed repeatedly in the
laboratory in tissue cultures or chick embryos and have
lost their capacity to induce full blown disease but
retain the Immunogenicity.
48
LIVE VACCINES Conti
Live vaccines are more potent immunizing
agents than killed vaccines because
Live
organisms multiply in the host and the resulting
antigenic dose is larger than what is injected.
Have
all the major and minor antigenic components.
Engage
certain tissues of body( intestinal mucosa by
polio).
Other
virus.
mechanisms
such as persistence of latent
LIVE VACCINES Conti
LIVE VACCINES should not be administered to persons
who have:
Immune deficiency disease, leukemia, lymphoma,
malignancy or therapy with corticosteroids, alkylating agents,
anti-metabolic agents or radiation and pregnancy.
When two live vaccines are required they should be given either
simultaneously at different sites or with an interval of at least
three weeks.
LIVE VACCINES
BACTERIAL
VIRAL
BCG
Oral polio
Typhoid oral
Yellow fever
Plague
Measles
Rubella
Mumps
Influenza
51
KILLED VACCINES
Organisms
They
are killed by heat or chemicals.
are generally safe but less effective than live
vaccines.
Killed
vaccine require a series of 2-3 doses and a
booster dose.
Usually
route.
administered by subcutaneous or intramuscular
INACTIVATED OR KILLED
VACCINES
BACTERIAL
VIRAL
Typhoid
Rabies
Cholera
Salk polio
Pertusis
Influenza
C S Meningitis
Hepatitis B
Plague
Japanese encephalitis
KFD
53
TOXOIDS
Certain
The
organisms produce exotoxins eg diphtheria and tetanus
toxins produced by these organisms are detoxicated and used
in preparation of the vaccines.
The
antibodies produced neutralize the toxic moiety produced
during the infection.
The
toxoid act against the
toxin
rather than acting against the
organism.
Toxoid
agents.
preparations are highly efficacious and safe immunizing
CELLULAR FRACTIONS
Vaccines
are also prepared from extracted cellular
fractions e.g.
Meningococcal
vaccine from the polysaccharide
antigen of the cell wall.
Pneumococcal
vaccine from the polysaccharide
contained in the capsule of the organism.
Hepatitis
B polypeptide vaccine.
COMBINATIONS

When more than one kind of immunizing agent is included in
the vaccine it is called a mixed or combined vaccine.

Combined vaccines simplify administration, reduce cost.

Examples are DPT, DT, DP, DPT and Typhoid vaccine, MMR,

DPTP(DPT plus inactivated Polio.
56
ANTISERA OR ANTITOXIN
Antisera
Passive
are the materials prepared in the animals.
immunization is achieved by administration of
Antisera.
Antitoxins
prepared from non human sources against
Tetanus, Diphtheria, Botulism, Gas gangrene and
snake bite.
IMMUNOGLOBULINS
Human
Normal Ig
Human
Non Human
Specific Ig Antisera
Hepatitis A
Rabies
Diphtheria
Measles
Tetanus
Tetanus
Mumps
Gas gangerene
Hepatitis B
Botulism
Varicella
Rabies
Diphtheria
58
What is cold chain?


The term cold chain is the name given to
the system of transporting and storing
vaccines within the safe temperature
range of 2ºC - 8ºC.
The cold chain involves all the people,
equipment and procedures which ensure
that an effective vaccine reaches the
people who need it - usually children.
59
Cold chain system





The cold chain system comprises three major
elements:
· Personnel, who use and maintain the equipment
and provide the health service;
· Equipment for safe storage and transportation of
vaccines; and
· Procedures to manage the Programme and
control distribution and use of the vaccines.
Competent personnel and efficient procedures are a
vitally important part of the cold chain system:
60
Provincial
Divisional
District
Tehsil
RHC
BHU
61
62
How much vaccine is needed at each
level of the cold chain?

To estimate the quantity of vaccine needed for primary
immunization in any area (i.e., for a health facility), the
following information will be needed:

the number of children in the area to be immunized during
the next 12 months;

the number of doses needed per child for each vaccine;

the estimated index of vaccine use (also called wastage
factor) for each vaccine;

the number of vaccine deliveries planned during the next 12
months;

the amount of reserve vaccine stock (in %) to be kept in the
main store of the area;

the balance of vaccine stock remaining in the main store at
the date of the estimate.
63
Technical features that impact on vaccine storage and temperature
monitoring
64
Vaccine carriers
65
66
How does the VVM work?
The VVM has a heat sensitive square in a circular disk that registers a gradual and progressive
colour change with exposure to heat. The inner square is initially white, but becomes darker with
exposure to heat. All the time the inner square is lighter than the surrounding disk, the vaccine is
safe to use. If the inner square becomes of equal colour or darker than the surrounding disk, the
vaccine must NOT be used.
67
68
REMEMBER - All vaccines can be safely kept
in the temperature range 2ºC - 8ºC.

Vaccines can become less effective or even lose
their effectiveness altogether if they:

Get too hot

Freeze

exposed to light
69
DO NOT FREEZE THESE VACCINES
•DTP (Diphtheria-tetanus- pertussis vaccine "Triple
antigen")
•CDT (Combined diphtheria-tetanus vaccine)
•ADT (Adult diphtheria-tetanus vaccine)
•TT (Tetanus toxoid) ·
•Hib vaccines
• Hepatitis B Vaccine ·
•Hepatitis A Vaccine
• Monovalent pertussis vaccine
•Influenza vaccine
DO NOT EXPOSE THESE VACCINES TO LIGHT:
•BCG Vaccine
•Reconstituted MMR (measles/mumps/rubella) vaccine
•Oral poliomyelitis vaccine (OPV)
71
Dosage
72
73