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Prepared by: Anish Dhakal (Aryan)
anishdhakal718@gmail.com
MBBS Student
Patan Academy of Health Sciences

2. OBJECTIVES
 To define vaccine
 To discuss the types of
vaccines
 To discuss the Expanded
Program on Immunization
(EPI) schedule of Nepal
with OPV and IPV rationale
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3. WHAT IS VACCINE?
 Vaccine is an immuno biological substance
designed to produce specific protection against
a give disease
 Artificial Active Immunity
 Triggers humoral and cell mediated immune
response or both mimicking the natural infection
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4. TYPES OF VACCINES
 Live attenuated vaccines
 Inactivated /Killed vaccines
 Toxoid vaccines
 Cellular fraction / sub unit
 Conjugate vaccines
 Acellular vaccines
 DNA vaccines
 Recombinant vaccines
 Combination vaccines
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5. LIVE ATTENUATED VACCINE
 Prepared from live (generally attenuated) organism
 Organisms lost pathogenicity but retain immunogenicity
due to repeated culturing
 More potent than other vaccines because:
 Resultant antigenic dose is higher and sustained
 Contain all major and minor antigenic components
 Engage body tissues causing persistent immune response
 Viral live vaccines are provoke excellent immune response
 Immunization usually with a single dose
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6. LIVE ATTENUATED VACCINE
 Example of live vaccines
include Measles, Mumps,
BCG, Influenza, Rubella and
oral polio vaccine
 Contraindication
 Immunocompromised state
(due to therapy or disease)
 Pregnancy
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7. INACTIVATED OR KILLED VACCINE
 Organism are killed by heat or
chemical and injected into body
 Usually safe, requires adjuvants
and less efficacious than live
vaccine
 Requires booster dose
 Examples include J.E , Rabies,
Hepatitis B, IPV
 Contraindication
 Severe local or general reaction
in previous dose 7

8. TOXOID VACCINES
 Toxins produce by organism
are detoxicated and used in
preparation of vaccine
 Antibodies produced
neutralized the toxin rather
than act upon the organism
 Toxicity is lost but antigenicity
is retained
 Examples – Diphtheria and
Tetanus
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9. CELLULAR FRACTION / SUB UNIT
 Conjugate vaccines
 Pieces from coats of bacteria are
linked to carrier protein which cause
immune response
 Example – Hib
 Acellular vaccines
 Vaccine that contain cellular material but
not complete cell
 Only those antigen/epitopes that evoke
best immune response are selected
 Example - Pertussis
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10. DNA VACCINES
 Genes for microbe’s antigen are introduced into
body, some cells take up the DNA
 Microbe’s DNA then instructs cell to synthesize
antigens
 The person’s own body become vaccine making
factories creating antigens required to provoke
immune response
 DNA vaccines being tested in humans include
those against the viruses that cause influenza and
herpes
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12. RECOMBINANT VECTOR VACCINES
 Similar to DNA vaccines
except use of a vector
 Use of attenuated and live
virus or bacterium to introduce
microbial DNA to the body
 Example – Hep. B , Cholera
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13. COMBINATION VACCINES
 More than one kind of
immunizing agent is
included in the vaccine
 It simplifies
administration and
reduces cost
 Example - DPT, DT,
MMR
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15. POLIO VACCINE: OPV VS IPV

16.  Routine immunization with OPV must cease after the
eradication of poliovirus because of the danger of
outbreaks of circulating vaccine-derived poliovirus and
the risk of VAPP (Vaccine Associated Paralytic
Poliomyelitis)
 In the regions of the world in which wild-type poliovirus has
been eliminated, moving to an IPV or IPV/OPV sequential
schedule will reduce or eliminate the risk of VAPP and
outbreaks of circulating vaccine-derived poliovirus, as well as
increase the likelihood of countries agreeing to stop
administering OPV after eradication is achieved.
 IPV could also be used with OPV in routine schedules to
increase immune responses and to decrease the circulation of
wild-type poliovirus in countries in which transmission has not
been stopped.

17. IPV – RATIONALE
 Type 2 poliovirus mutates into virulent form
 IPV contains killed virus, so IPV mitigates this risk
 IPV in addition to OPV provides better immunity
 All countries switched from tOPV to bOPV (minus type 2) 2016
 Introduction of IPV before this ensure protection against type 2
 Once virus circulation stopped everywhere, OPV withdrawn
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