The document discusses various types of immunization including their goals, definitions, and details. It covers: - Passive and active immunity from natural and artificial sources - Types of vaccines including live attenuated, inactivated, subunit, toxoid, and conjugate - Details on specific vaccines like BCG, polio, diphtheria, hepatitis B, pneumococcal, rotavirus, and measles - Schedules, efficacy, advantages, side effects and contraindications of different vaccines - The importance of vaccination programs in reducing disease prevalence globally

1. Immunization
Biniyam Nigussie , MD

2. Goal
• To prevent disease in individuals.
(Immediate)
• To eradicate a communicable
disease. (Ultimate)

3. Definitions…
• Immunity  the ability of the body to
recognize and destroy foreign antigenic
material like bacteria, viruses and proteins
leading to resistance to infection.
• Innate immunity is the natural resistance of
the human being with in his genetic make up
to certain animal infection.

4. Passive & active immunity
natural immunity artificial immunity
post-
infection
active
maternal
antibody
transfer to
the fetus
passive
exposure to
antigen
active
immunisation
active
injection of
antibodies
passive
immunisation
passive

5. Type of Immunity
1. Passive (Immediate protection, only last for some
wks or month)
- Transplacental immunity
- Antibodies
2. Active (protection is produced by individuals)
- Natural as observed after natural infections & may
be life long.
- Acquired by administration of vaccine.
3. Herd immunity:- If the no of people in the
community who have active immunity against an
infection exceeds a critical level.

6. Active immunization (vaccination)
• Vaccine is an antigen, when administered
stimulates specific antibody formation with
resulting immunity against the particular
disease.
• It is prepared from
- Live attenuated organism:
- Killed organism:
- Toxoid:
- Genetic engineered

7. Live Attenuated Vaccines
• Attenuated form of the "wild type" virus or
bacteria
• Must replicate to be effective
• Immune response similar to natural infection
• Usually effective with one dose
• Usually mild but severe reactions are possible;
occur after an incubation period (7-21 days)
• Interference from circulating antibody
• Unstable

8. Live Attenuated Vaccines
Viral
‒ Influenza (intranasal)
‒ Measles
‒ Mumps
‒ Polio (oral)
‒ Rotavirus
‒ Rubella
‒ Vaccinia
‒ Varicella
‒ Yellow fever
Bacterial
‒BCG
‒Oral typhoid

9. Live-attenuated vaccines
strain attenuation in cell culture
wild virus replication in
unfavourable conditions
the process is repeated
many times …
… to produce an attenuated
strain, unable to cause disease

10. Live-attenuated vaccines
advantages
• mimic natural infection
• produce a large
antigenic stimulus
• generally induce T&B
lymphocyte responses
• provide long-lasting
protection

11. Live-attenuated vaccines
disadvantages
• may retain some pathogenicity
• may revert to virulence
• may not be safe enough to vaccinate highly
immuno-compromised subjects
• require a good cold chain

12. Inactivated Vaccines
• Cannot replicate
• Minimal interference from circulating antibody
• Generally not as effective as live vaccines
• Generally require 3-5 doses
• Immune response mostly humoral
• Antibody titer diminishes with time

13. Inactivated Vaccines
• Whole virus:
– Polio, hepatitis A
• Bacteria:
– Pertussis, cholera, typhoid
• Protein-based subunit:
– Hepatitis B, influenza, acellular pertussis
• Toxoid:
– Diphtheria, tetanus
• Polysaccharide-based:
– Pure: pneumococcal,meningococcal
– Conjugate: pneumococcal, Hib, meningococcal

14. Killed, inactivated vaccines
the pathogen is grown under
suitable conditions
purified and treated
with heat or chemicals
… so that it is inactivated but
still immunogenic

15. Killed, inactivated vaccines
disadvantages
• often less effective than live-attenuated vaccines
• several doses needed for long-term
protection
• repeat administration may increase
reactogenicity(eg, whole cell pertussis vaccines)
• limited production capacity & higher price

16. Determinants of the immune
response
• Chemical and physical state of the antigen
• Mode of administration
• Host factors –
– Age,
– Nutrition
– Preexisting antibodies

17. Advantages of immunization
• Saves the lives of millions of children.
• Very cost- effective.
• Led to global eradication of small pox.
• Elimination of poliomyelitis  some continents.
• More than 95% reduction of Haemophilus
Influenza type B desease.
• In USA it eliminated completely congenital
rubella syndrome, tetanus, polio and diphtheria

18. Benefits of vaccination
20
40
60
1980 1990 2000
polio - worldwide
reported
cases
(000s)
EPI implemented
1950 1960 1970 1980
measles - US
vaccine
introduced
20
40
60
1940 1950 1960
Diphtheria – England & Wales
reported
cases
(000s)
vaccine introduced

19. Expanded Program of
Immunization (EPI)/WHO
• Aims to provide free immunization
• Started in 1974
• Main purpose:
- Prevent childhood diseases
- Provide high quality vaccines
- Surveillance of these diseases
• Schedule of immunization is designed according to
epidemiological terms of diseases together with
sociocultural &economic factors.

20. Schedule in Ethiopia
Age Vaccine Route
Birth BCG/OPV0 ID/PO
6wks Pentavalent1/PCV1/OPV1/Rota IM/PO
10wks Pentavalent2/PCV2/OPV2/Rota IM/PO
14wks Pentavalent3/PCV3/OPV3 IM/PO
9month Measles SC

21. EPI…
• Any missed dose should be given at any
subsequent visit when indicated and feasible.
• Pertussis is not given after 7 years.
• Infants born to HbSAg positive mothers
should receive 0.5 ml of Hepatitis Immune
globulin (HBIG) and Hepatitis b vaccine with in
72 hours of birth.

23. BCG (Bacillus Calmettie Guerin)
• Protects against TB.
• Limits infection and hematogenous spread of
the disease.
• Attenuated M. bovis
• Sensitive to heat and light
• Efficacy as high as 80% for severe form of the
disease and 0-80% for pulmonary TB.
• Given at birth of as soon as possible (3/12 of
life).
• Site :- right upper arm

24. S/E
• Small swelling at the site of injection with in
2weeks and after a week it form a small abscess,
ulcerate and leaves a scar.(Kochs Phenomenon)
• The scar has 2 uses
- Witnesses the child is vaccinated
- Good degree of immune response
• Deep abscess and involvement of LN (axillary
LAP
• Extension of infection to bones Osteomyelitis

25. Oral Polio Virus
• Live attenuated viruses of the 3 and 2
types(Sabin).
• It produce life long local intestinal & systemic
immunity.
• Damaged by heat but not by freeze(Cryostable).
• 72-98% efficacy in hot climates , lower
protection against type III.
S/E
– Doesn’t have common S/E
– Rarely poliomyelitis has been reported(1:106 va)
Diarrhea give the vaccine and repeat to the
dose because it may not be effective.

26. Pentavalent Vaccine
• The Pentavalent vaccine combines five
different vaccines in one injection to protect
against
- Haemophilus influenzae type B (Hib) disease
- Diphtheria
- Pertussis
- Tetanus
- Hepatitis-B

27. Tetanus toxoid
• It is inactivated by heat and freeze.
• If the person has previously suffering from the
disease, he should be vaccinated.
• Booster injection should be given after every
5-10yrs.
• Efficacy:- >95% (>80% after 2 doses)
• S/E :- extremely rare.

28. Why?
• If the person has previously suffering from the
disease, he should be vaccinated.

29. Diphteria toxoid
• Damaged by freezing and heat.
• Efficacy:- >80%
• Duration of immunity: variable, probably
around 5 yrs
• S/E :- no significant adverse reaction have
been associated.

30. Pertussis vaccine
• It is killed B .pertusis
• Sensitive to heat.
• Efficacy:- variable; around 80% for severe
disease
• Duration of immunity:- unknown
• Dtap Vs Tdap

31. Precaution
• Never give to children >7yrs
S/E
• Fever (high grade), local soreness (3-4days), an
abscess at the site of injection, febrile
convulsion 0.3-9/100,000dose
• Permanent brain damage, encephalitis (0.3-
0.6/100,000dose & shock like state are
common >6months age

32. C/I
• Convulsion with in 3 days following vaccine.
• Shock like state
• High grade fever (400C)
• Progressive neurologic deficit

33. Hepatitis B vaccine
• It is inactivated product produced by genetic
engineering.
• It protects the child against hepatitis B.
• S/E= No
Haemophylus Influenzae Type B vaccine
• It consists of a capsular polysaccharide
conjugated to a protein.
• Keep it at +20C -+80C, don’t freeze

35. Pneumococcal Polysaccharide Vaccine
• Purified capsular polysaccharide antigen from 23
types of pneumococcus
• Account for 88% of bacteremic pneumococcal
disease
• Cross-react with types causing additional 8% of
disease
• Less effective in preventing pneumococcal
pneumonia

36. Problems with polysaccharide vaccine
• Not effective in children less than 2 years
• No effect on nasal carriage
• No herd effect
• ≈
• Absence of immunologic memory
• Antibody level to several serotypes decline to
pre-vaccination values within 3-7 years ≈ to a
decline of clinical protection

37. Conjugate Vaccine
• A new generation of pneumococcal vaccines
• Coating removal of the capsular
polysaccharide
• 7 (9, 10 or 13, …) types of saccharide is
separately activated and conjugated to protein
carrier
• Conjugates are mixed to formulate vaccine

38. Conjugate Vaccine
• Induce a T-cell dependent immune response.
• Protective even in children under two years of
age,
• May reduce pneumococcal transmission
through a herd effect

39. Pneumococcal Conjugate Vaccine
• Highly immunogenic in infants and young
children, including those with high risk medical
conditions
• >90% effective against invasive disease
• Less effective against pneumonia and acute
otitis media

40. Pneumococcal Conjugate Vaccine
• Routine vaccination of children age <24
months and children 24-59 months with high
risk medical conditions
• Doses at 6, 10 and 14weeks booster dose at
12-15 months
• Unvaccinated children >7 months require
fewer doses

41. Pneumococcal Vaccines Adverse Reactions
• Local reactions
–polysaccharide 30%-50%
–conjugate 10%-20%
• Fever, myalgias
–polysaccharide <1%
–conjugate 15%-24%
• Severe adverse reactions rare

42. Rotashield Implemented in 1998

43. A Setback – Rotashield Withdrawn Within 1 Year
Because of Association with Intussusception
1 intussusception per 10,000 vaccinated infants

44. Licensed Rotavirus Vaccines
Rotarix® RotaTeq®
Safety = =
Efficacy 90-100% severe
74-85% any severity
90-100% severe
74-85% any severity
Antigen Monovalent HRV
G1P[8]
Pentavalent
bovinehuman
reassortant
Schedule 2 doses 3 doses
Protection against
severe infx
2 years 2 years

47. Measles
• Live attenuated measles virus.
• Damaged by heat.
• 9month is the age if given earlier the maternal
antibody will damage the vaccine.
• Some recommend the vaccine at the age of 6
month because there is risk of acquiring virus
at the age < 9months.

48. S/E
• Fever (after 1wk) & a mild measles like rash
self limited.
Causes of failure
a. Destroyed vaccine by improper storage
b. Sustained transplacental immunity that may
remain for up to 15months of age.

49. N.B
• Practically there are no major CI for
vaccination.
• No BCG for AIDS patient but can be given for
sero positive children.
• Potentially depends on the Cold Chain (I.e. a
system of storage
• T0 maintained all the way b/n the site of
production & site of administration (+2oC-
+0.80C)

50. Strategies to Boost the coverage
• If the child is well enough to go home , he so
after immunized
• Mild or moderate illness, fever, malnutrition
can be vaccinated.
- Vaccinate children who come for other illness.
- Educate mother very well to reduce the no of
defaulters.

51. Mass Immunizations
• Used in regions or countries where the
immunization rate is low.
• Control an unexpected out-breaks.

52. • Contraindication
• Anaphylactic reaction, Shock like state
• Moderate to severe illness
• Live-attenuated vaccines for severely
immunosuppressed patients (exception is
measles) C
• Convulsion with in 3 days following vaccine.
• High grade fever (40C)
• Progressive neurologic deficit (GBS)

53. • The following are not contraindications
Moderate fever after prior vaccine dose
Moderate local reaction after inject able vaccine
Minor illness with fever <38.5⁰c
Prematurity
Malnutrition
Family history of convulsion
Treatment with antibiotics, low dose corticosteroids
or locally acting steroids
Chronic diseases of the heart, lung, kidney and liver
Stable neurological conditions like cerebral palsy and
down syndrome
History of jaundice after birth

54. The Cold Chain
• Vaccines are sensitive to heat and freezing.
• They must be kept and transported at the correct
temperature from time of manufacturing to
administration.
• The System used for keeping and distributing
vaccines in good condition is called The Cold Chain
• Its main role is to maintain potency of vaccines.
• It consists of a series of storage and transport links