This document provides an overview of vaccination, including: - A brief history of vaccination from early attempts in China to Edward Jenner's smallpox vaccine. - An introduction defining vaccines and their ability to produce immunity against diseases. - Descriptions of the different types of vaccines including live, attenuated, inactivated, subunit, conjugate, and recombinant vaccines.

1. Prabin Shah
BScMLT,
MSc(Biochemistr
y)

2. Contents
 History
 Introduction
 Immunity and its types
 Principal of vaccination
 Types
 Vaccination schedule
 Special vaccines
 Hazards of vaccination

3.  First recorded attempt at immunization occurred in 6th
century China.
 drying & grinding up smallpox scabs & blowing them
with a straw into the nostrils of immuno-compromised
family members.
 By the 10th century, this practice had changed to the
deliberate inoculation of dried pus from the smallpox
pustules of one patient into the arm of a healthy
person,(variolation)
 This method was used in parts of the Far East for
centuries before Lady Mary Montagu brought it to
England in 1721 from Istanbul.

4.  Eventually, first really effective vaccine was developed by the
English physician Edward Jenner in 1796.
 NOW while many advances have occurred in the last two
centuries, science is poised for even more in the future.
 Today, researchers are working to improve existing vaccines and
to search for vaccine to fight HIV/AIDS, cancer and other diseases.

5. Introduction
 Vaccines “With the exception of safe water, no other
modality, not even antibiotics, has had such a major
effect on mortality reduction…”
 The term “vaccine” was coined by Louis Pasteur.
 The term vaccine was derived from “vacca”, meaning
cow, since Edward Jenner used cowpox virus (Vaccinia)
to prevent smallpox infection.
 A vaccine is an immuno-biological substance designed
to produce specific protection against a given disease.
 A vaccine is “antigenic” but not “pathogenic”.
 Vaccines have profoundly reduced the prevalence and
impact of many infectious diseases that were once
common and often deadly.

6. Properties of an ideal vaccine
(easy to define, difficult to achieve)
6
 Give life long immunity
 Broadly protective against all variants of
organism
 Prevent disease transmission
 Rapidly induce immunity
 Effective in all subjects (the old & very young)
 Transmit maternal protection to the foetus
 Require few immunisations to induce protection
 Not need to be administered by injection (oral,
intranasal, transcutaneous)
 Stable, cheap & safe

7. Routes of administration
 Deep subcutaneous or intramuscular route
(most vaccines)
 Oral route (sabine vaccine, oral BCG vaccine)
 Intradermal route (BCG vaccine)
 Scarification (small pox vaccine)
 Intranasal route (live attenuated influenza vaccine)
Scheme of immunization
 Primary vaccination
 One dose vaccines (BCG, variola, measles, mumps, rubella,
yellow fever)
 Multiple dose vaccines (polio, DPT, hepatitis B)
 Booster vaccination
 To maintain immunity level after it declines after some time has
elapsed (DT, MMR).

8. Types of immunity
Vaccination is artificially acquired active
immunity

9. Primary
response to a
vaccine
most current
vaccines induce
protective
antibodies
9
Principle of vaccination

10. Secondary
response to
an infection
primed by
vaccine
10

11. Primary & secondary antibody responses
vaccination & infection
11

12. Types of vaccines
 Live vaccines
 Attenuated live vaccines
 Inactivated (killed vaccines)
 Subunit vaccines
 Conjugate vaccines
 Surface antigen (recombinant) vaccines.
 DNA vaccine
 Anti-idotypic vaccine

13. Live vaccine
 Live vaccines are made from live infectious agents
without any amendment or changes.
 The only live vaccine is “Variola” small pox vaccine,
made of live vaccinia cow-pox virus (not variola virus)
which is not pathogenic but antigenic, giving cross
immunity for variola.
Live Attenuated Vaccines
 Virulent pathogenic organisms are treated to become
attenuated and avirulent but antigenic.
 They have lost their capacity to induce disease but
retain their immunogenicity.
 These vaccines may be given by injection or by the
oral route.

14. Growing in foreign host in condition
that makes it’s a virulent
 Administration orally, intradermal, intranasal,
subcutaneous
 Examples: Vibrio ,Salmonella , BCG, Polio, JE,
Yellow Fever Influenza , MMR, Chicken pox, Small pox

15. Advantages
 stimulate generation of cellular as well as humoral
immune responses.
 Since these can multiply in the host, single administration
of vaccine produce long-lived immunity.
 Multiple booster doses may not be required
 Oral preparations are less expensive than giving injections.
 elimination of wild type virus from the community
Disadvantages
 May very rarely convert to its virulent form and cause
disease.
 Live vaccines cannot be given to immuno-suppressed
individuals,can cause serious illness or death in the
vaccine recipient.
 Since they are live and because their activity depends on
their viability, proper storage is critical.

16. Killed Vaccines
 When it is unsafe to use live microorganisms to prepare
vaccines, they are killed or inactivated.
 Organisms are killed or inactivated by treatment with using
heat, formaldehyde or gamma irradiation so that they cannot
replicate at all, but remain antigenic.
 usually safe but less effective than live attenuated vaccines.
 route of administration Intramuscular(IM), Sub-
cutaneous(SC)
 Examples: Salmonella typhi, Vibrio cholerae, Yersinia pestis,
Bordetella pertussis, Poliomyelitis Salk, JE virus, Rabies virus,
Influenza virus, Hepatitis A

17. Advantages
 Safe to use and can be given to immuno-deficient and
pregnant individuals.
 Cheaper than live attenuated vaccine
 Storage not as critical as live vaccine
Disadvantages
 microorganisms cannot multiply so periodic boosters
must be given to maintain immunity.
 Only humoral immunity can be induced.
 Most killed vaccines have to be injected.
 Some vaccines such as Bordetella pertussis induce ill
effects like post-vaccinial encephalomyelitis.
 Inactivation, such as by formaldehyde in the case of
the Salk vaccine, may alter antigenicity.

18. Subunit vaccines
 Subunit vaccines contain purified antigens instead of
whole organisms.
 Such a preparation consists of only those antigens that
elicit protective immunity.
 Subunit vaccines are composed of toxoids, subcellular
fragments, or surface antigens
 The effectiveness of subunit vaccines in increased by
giving them in adjuvants.
 Route of administration Intramuscular
Examples: Cell wall polysaccharide (Hemophilus
influenzae,Nesseria meningitides, Streptococcus
pneumoniae, Group B Streptococcus ,Salmonella typhi)
Toxoid (Tetanus, Diphtheria)
Membrane proteins (Influenza virus, HepatitisB)

19. Advantages
 can safely be given to immuno-suppressed people
 less likely to induce side effects.
Disadvantages
 Antigens may not retain their native conformation, so
that antibodies produced against the subunit may not
recognize the same protein on the pathogen surface.
 Isolated protein does not stimulate the immune system
as well as a whole organism vaccine.

20. Conjugate vaccines
 is a type of vaccine that is created by joining
an antigen to a protein molecule.
 usually used to immunize babies and children against
bacteria that have polysaccharide capsular
 The immature immune systems of very young people
often have difficulty recognizing certain antigens, so
ordinary vaccines may not be effective for some
diseases.
 A conjugate vaccine, therefore, usually consists of a
polysaccharide antigen combined with a carrier protein.
 The combination of the antigen with the protein creates
a substance that is more easily recognizable to the
white blood cells in the human blood, resulting in a
stronger immune response.
Examples: Tetramune vaccine,which combines the tetanus
and diphtheria toxoids, whole-cell pertussis vaccine,
and H. influenzae type b conjugate vaccine.

21. Recombinant vaccine
 The vaccines are produced using recombinant DNA technology or
genetic engineering.
 Recombinant vaccines are those in which genes for desired antigens
of a microbe are inserted into a vector.
 Examples: Hepatitis B, Diptheria, Cholera, Tetanus,

22. Advantages
 Those vectors that are not only safe but also easy to
grow and store can be chosen.
 Antigens which may cause damaging responses can
be eliminated from the vaccine.
 Example Cholera toxin A can be safely removed from
cholera toxin.
Disadvantages
 Since the genes for the desired antigens must be
located, cloned, and expressed efficiently in the new
vector, the cost of production is high.
 When engineered vaccinia virus is used to vaccinate,
care must be taken to spare immunodeficient
individuals.

23. DNA Vaccines
 DNA vaccines are being hailed as the most promising of
all of the newer approaches to immunization.
 These vaccines are still in experimental stage. Like
recombinant vaccines, genes for the desired antigens
are located and cloned.
 DNA vaccines have induced both humoral and cellular
immunity.
 Route of administration gene gun method, intradermal,
get injection
 Examples: bird flu DNA vaccine

24. Advantages
 DNA is very stable,hence storage and transport are easy.
 DNA sequence can be changed easily in the laboratory.
 Inserted DNA does not replicate and encodes only the
proteins of interest.
Disadvantages
 Induction of autoimmune responses:
anti-DNA antibodies may be produced against introduced
DNA.
 Induction of immunologic tolerance:
The expression of the antigen in the host may lead to
specific non-responsiveness to that antigen.

25. Anti-idiotypic vaccine
 This unique amino acid structure in the antibody is known as
the idiotype, which can be considered as a mirror of the
epitope in the antigen.
 Antibodies can be raised against the idiotype by injecting the
antibody into another animal.
 This anti-idiotype antibody mimics part of the three
dimensional structure of the antigen. This can be used as a
vaccine.
 When the anti-idiotype antibody is injected into a vaccine,
antibodies (anti-idiotype antibodies) are formed that
recognize a a structure similar to part of the virus and might
potentially neutralize the virus.
 Advantage:
 Antibodies against potentially significant antigen can be produced.
 Disadvantage:
 Only humoral immunity is produced. There is no cellular immunity and poor
memory. Identification and preparatistructure similar to part of the virus
and might potentially neutralize the virus.

26. Advantage
 Antibodies against potentially significant antigen can
be produced.
Disadvantage
 Only humoral immunity is produced. There is no
cellular immunity and poor memory.
 Identification and preparation of idiotypes is labor
intensive and difficult.

27. Vaccination of those at occupational risks
 Depending upon the organisms they are exposed to
vaccination can be done
Occupation Vaccines
Laboratory personals Q fever
Australian bat lyssavirus (ABL) and
rabies
Anthrax
Vaccinia poxviruses
Poliomyelitis
Typhoid,
Yellow fever
Meningococcal disease
MMR
Japanese encephalitis
HepatitisB

28. Vaccination for travellers
 Varies according to the country of arrival and departure.
 Common vaccines according to the country traveled to:
 TAB, YF, cholera, meningiococcal, pneuomococcal,
 HIB, influenza, rabies, plague, Japanese encephalitis,
 tickborn encephalities, measles, Hepatitis B,
 Hepatitis A, Tetanus, poliomyletis,Typhoid,
 Hajj for instance necessates meningococcal vaccination from
all over
 Yellow Fever from places like south Africa, and cholera from
places like India.
Vaccines against bioterrorism
 Anthrax
 Small pox
 Plague

29. Hazards of Immunization
 No immune response is entirely free from the
risk of adverse reactions or remote squeal.
 The adverse reactions that may occur may be
grouped under the following heads:
 Reactions inherent to inoculation
 Reactions due to faulty techniques
 Reactions due to hypersensitivity
 Neurological involvement
 Provocative reactions
 Others

30. Still more to done …………………
 Around 24 million children under one year old – almost 20% of the
children born every year – are not being reached with vaccines.