Types of vaccines

Types of Vaccines with live attenuated, inactivated up to recombination technique. OPV and IPV difference and rationale to replace OPV with IPV. EPI schedule of nepal

1. 1 Prepared by: Anish Dhakal (Aryan) [email protected] 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 2

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 3

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 4

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 5

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 6

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 8

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 9

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 10

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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 12

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 13

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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 17

18. 18 THANK YOU