‫بسم هللا الرحمن الرحيم‬
IMMUNIZATION
Immunization
• Immunization
– The creation of
immunity usually against
a particular disease;
especially : treatment (as
by vaccination/
immunoglobulin) for the
purpose of making a
person immune to a
particular pathogen
Widespread vaccination led to small
pox eradication
• Widespread immunity
due to vaccination is
largely responsible for the
worldwide eradication of
a very deadly and lethal
virus called smallpox virus
and the restriction of
diseases such as polio,
measles, and tetanus
from much of the world.
1798 vaccine developed
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All viruses within the Orthopoxvirus
genus are so closely related that
infection with one induces an
immunity to all other members
In 1796, an English doctor Edward
Jenner observed, milkmaids
infected with cowpox (a very mild
disease) never seemed to get
smallpox.
He inoculated , an 8 year old boy,
with cow pox virus and a month
later with live smallpox virus.The
boy was completely protected and
did not show any symptoms.
This was the first ever vaccine,
infact the word vaccine is derived
from Latin word for cow, vaccinus
1967, WHO campaign
• In 1967, WHO launched
an intensified plan to
eradicate smallpox
• Worlds last indiginous
patient of small pox was a
hospital cook in Merka,
somalia, in October 26,
1977.
• Finally in 1979 WHO
declared small pox
eradicated from the world
Types of immunization
• Active immunization
– Active immunization is the
induction of immunity after
exposure to an antigen
• Natural
– Exposure to microbe
• Artificial
– use of vaccine.
• Passive immunization
– Use of preformed antibodies
from another host
• natural
– Mother to fetus
• Artificial
– Use of immunoglobulins
Vaccination
• Vaccination
– Artificial induction of
immunity by using vaccines
• Vaccine
– A preparation of a weakened
or killed pathogen, such as a
bacterium or virus, or of a
part of the pathogen's
structure that upon
administration stimulates
antibody production or
cellular immunity against the
pathogen but is incapable of
causing severe infection itself
Types of vaccines
• Three types of vaccines
– Live attenuated vaccine
– Killed vaccine
– Subunit vaccine
Live attenuated vaccine
• Live attenuated vaccine
(‫)لقاح حي موهن‬
– A live attenuated vaccine
contains live microbe
whose pathogenicity
(disease causing ability)
has been
attenuated(reduced) but
it still retains its
antigenicity to induce
immunity
Advantages
– Live attenuated
microbes induce longer
and greater immunity as
they multiply in the
body
– Excretion of microbe by
the vaccinated individual
transmits it to other
nonimmune contacts so
that they also get
vaccinated
Disadvantages
• An important problem is
that the live microbe may
change back to normal
microbe causing disease;
only polio virus has this
problem
• Maintenance of cold
storage
• Should not be given to
immunocompromised and
pregnant woman
Killed vaccine
• Killed vaccine or inactivated
vaccine
– Vaccines of this type are
created by inactivating a
pathogen, typically using heat
or chemicals such as formalin.
This destroys the pathogen’s
ability to multiply, but keeps it
antigenicity“intact” so that the
immune system can still
recognize it.
• Toxoid vaccine is inactivated
exotoxins of bacteria whose
toxicity is destroyed but
antigenicity is retained e.g
diphtheria and tetanus toxoid
Advantages & disadvantages
• Advantages
– Cannot revert back to
normal
– No cold chain
• Disadvantages
– Immunity is shorter and
weaker
– No immunity of the
contactss
Subunit vaccine
• Subunit vaccines use only part of
a microbe to provoke an immune
response.
– isolating a specific protein from a
pathogen
• Recombinant vaccine
– A gene from the pathogen, coding
for a protein antigen is inserted
into genome of a producer cell
which expresses it.
– Hepatitis B vaccine contains one
of the viral envelope proteins,
hepatitis B surface antigen
(HBsAg). It is produced by yeast
cells, into which the genetic code
for HBsAg has been inserted
– The expressed protein is isolated
and injected as vaccine
Conjugate vaccine
• Conjugate vaccines are
made using a part from the
pathogen and chemically
attaching it to a carrier
protein to create a more
powerful immune response:
– typically the “piece” of
bacteria being presented
would not generate a strong
immune response on its own,
while the carrier protein
would.
– e.g pneumococcal vaccine in
children
Immunoglobulins
• Passive immunity
• Use of preformed antibodies
developed in another host
• Immediate protection as
compared to vaccines which
take few days to stimulate
antibody production
• Immunity is only short lived
( as long as the antibody
remains in the body)
• e.g hepatitis B passive
immunization with
immunoglobulins, rabies
passive immunization with
immunoglobulins
Hepatitis B post exposure prophylaxis
• Hepatitis post exposure
prophylaxis is an example of
both active & passive
immunization
• Immediately after exposure to
an hepatitis B positive case
prophylaxis is begin in the
form of one dose subunit
vaccine and one dose
HBIG(hepatitis B
immunoglobulin)
• HBIG provides immediate
protection (bind and remove
any virus)and vaccine will
stimulate a stronger antibody
production after a few days
Rabies Postexposure prophylaxis
• Rabies is a very fatal central
nervous sytem infection
caused by rabies virus
• It is 100% vaccine
preventable
• The virus has a long
incubation period of 1-3
months
• PEP is administered after
exposure to a rabid animal
before virus could enter
CNS
• PEP includes both active
and passive immunization
Rabies Postexposure prophylaxis
• Rabies immune globulin
(RIG)(passive immunization)
– Preformed antibodies in the
form of RIG is administered
– If possible, the entire dose of
RIG (20 IU/kg) should be
infused at the site of the bite;
otherwise, administered IM
at a distant site
• Rabies vaccine(active
immunization)
– The five doses of killed rabies
vaccine should be given on
days 0, 3, 7, 14, and 28
– 1ml IM dose in deltoid region
Tetanus postexposure prophylaxis
• Tetanus is a bacterial
infection after clostridium
tetani spores in soil enter
open wounds
• Patient goes into violent
spasms(muscle
contractions)
• It is common in
emergencies to give both
vaccine and
immunoglobulin after road
side injuries to prevent
tetanus(active-passive
immunization)
WHO EPI programme
• The World Health Organization
(WHO) initiated the Expanded
Program on Immunization
(EPI) in May 1974 with the
objective to vaccinate children
throughout the world.
• Vaccination coverage for
tuberculosis, diphtheria,
pertussis, tetanus, polio,
measles, hepatitis B,
Haemophilus influenzae type
B and rubella
• Started at birth
List of vaccines