Introduction: Vaccination is a critical tool for preventing the spread of infectious diseases. In this presentation, we will explore the science behind vaccines, their impact on public health, and some of the challenges and controversies surrounding vaccination. Section 1: Basics of Vaccination - We will start by discussing the basic principles of vaccination, including how vaccines work, the different types of vaccines, and how they are developed and tested. - We will also explore some common vaccine ingredients and their safety profile. Section 2: History and Impact of Vaccination - Vaccines have had a profound impact on public health, helping to eradicate or control many deadly diseases, such as smallpox, polio, and measles. - We will discuss the history of vaccination and some of the major milestones in vaccine development and deployment. - We will also look at the current state of vaccine-preventable diseases around the world and the role of vaccination in reducing their burden. Section 3: Vaccine Controversies and Challenges - Vaccination has not been without controversy, with some individuals and groups expressing concerns about vaccine safety, efficacy, and mandatory vaccination policies. - We will explore some of the most common vaccine myths and misconceptions and the scientific evidence behind them. - We will also discuss some of the challenges facing vaccination programs, such as vaccine hesitancy, access, and equity. Conclusion: Vaccination is one of the most effective ways to prevent the spread of infectious diseases and protect public health. Despite some challenges and controversies, vaccines have a proven track record of safety and efficacy. As we continue to face new and emerging infectious threats, vaccination will remain a critical tool in our fight against disease.

1. SRI PARAMAKALYANI COLLEGE
(RECREATED WITH A GRADE WITH CGPA OF 3.39 IN THE YEAR III CYCLE OF NAAC )
Affiliated to Manonmanium Sundaranar University
ALWARKURICHI-627412
POST GRADUATE & RESEARCH DEPARTMENT OF MICROBIOLOGY
(government aided)
ACADEMIC YEAR 2023-2024
II SEM CORE : IMMUNOLOGY
UNIT 5 - VACCINATION
SUBMITTED TO:
DR.S.VISWANATHAN HEAD
OF THE MICROBIOLOGY
DEPARTMENT
SUBMITTED BY:
PRIYADHARSHINI.G
1st Msc.MICROBIOLOGY

2. CONTENTS
Introduction
Vaccination principle
Types of vaccination
Applications

3. Introduction :
+ Vaccine is a biological preparation that improves immunity to a particular
disease. A vaccine typically contains an agent that resembles a disease-
causing microorganism, and is often made from weakened or killed forms
of the microbe, its toxins or one of its surface proteins.
+ The agent stimulates the body’s immune system to recognize the agent as
foreign, destroy it, and “remember” it, so that the immune system can
more easily recognize and destroy any of these microorganisms that it
later encounters.

4. History:
+ Edward Jenner (1749 – 1823) was an English
physician who observed that dairymaids who had
had cowpox did not get small pox. He then
vaccinated James Phipps, a boy of eight, with
matter from cowpox. After several weeks, it
became apparent that, because the boy had been
inoculated, he did not contract smallpox. Jenner
then published his results in Inquiry into the Cause
and Effects of the Variolae Vaccinae (1798), thus
proving the worth of vaccination (Vacca – cow).

5. Time line of vaccines :
+ 18th century :
+ 1796 First vaccine for smallpox, first vaccine for any disease
+ 19th century :
+ 1882 First vaccine for rabies
+ 20th century :
+ 1932 First vaccine for yellow fever
+ 1945 First vaccine for influenza 1952 First vaccine for polio
+ 1954 First vaccine for Japanese encephalitis
+ 1957 First vaccine for adenovirus-4 and 7

6. Time line of vaccination :
+ 1962 First oral polio vaccine
+ 1964 First vaccine for measles
+ 1967 First vaccine for mumps
+ 1970 First vaccine for rubella 1974 First vaccine for chicken pox
+ 1977 First vaccine for pneumonia
+ 1978 First vaccine for meningitis 1981 First vaccine for hepatitis B
+ 1992 First vaccine for hepatitis A
+ 1998 First vaccine for rotavirus

7. An ideal vaccine should be :
+ Good immune response:
+ Both Cell Mediated Immunity and antibody responses.
+ Immunity is long lived.
+ Single dose
+ Safety:
+ Danger of reversion to virulence, or Severe disease in
immunocompromised

8. + Stability:
+ Organisms in the vaccine must remain viable in order to
infect and replicate in the host
+ Vaccine preparations are therefore very sensitive to adverse
storage conditions Maintenance of the cold chain is very
important.
+ Expense:
+ Cheap to prepare

9. PRINCIPLE:
+ The basic principle of vaccination is ‘memory’ of the
immune system. Vaccines let the immune system to learn
how to fight the future onslaught of that pathogen for which
vaccine is being given. The body prepares antibodies in
response to vaccination and remembers this act.

11. Major sites for viral replication:
1. Mucosal surfaces of respiratory tract and GI tract.
2. Infection at mucosal surfaces followed by spread systemically
via blood and/or neurones to target organs.
3. Direct infection of blood stream via needle or bites and then
spread to target organs.

12. What happens when a vaccine enters
into our body ?
https://youtu.be/Atrx1P2EkiQ

13. CHILDHOOD IMMUNIZATION SCHEDULE:

14. Introduction of measles vaccine in 1662 :

15. There are several different types of vaccines. Each type is designed to teach your
immune system how to fight off certain kinds of germs—and the serious diseases
they cause. When scientists create vaccines, they consider:
#.How your immune system responds to the germ
#.Who needs to be vaccinated against the germ
#.The best technology or approach to create the vaccine
Based on a number of these factors, scientists decide which type of vaccine they
will make. There are several types of vaccines, including:
1Live-attenuated vaccines. 5.Conjugate vaccines
2.Inactivated or killed. 6.DNA vaccines
3.Toxoid vaccine. 7.Recombinant vaccine.
4.Subunit vaccine.

16. Live attenuated vaccine :
+ Live attenuated vaccines are a type of vaccine that contain live, weakened
forms of the pathogen. These vaccines are created by attenuating or
weakening the pathogen in the laboratory so that it can no longer cause
disease, but can still stimulate a protective immune response.
+ Live attenuated vaccines have several advantages over other types of
vaccines. They typically provide longer-lasting immunity than inactivated or
subunit vaccines, and they often require fewer doses to achieve immunity.
Additionally, live attenuated vaccines can stimulate a broader range of
immune responses, including both humoral (antibody-mediated) and cellular
(T cell-mediated) immunity.

17. + However, there are also some limitations to live attenuated vaccines.
Because they contain live, albeit weakened, forms of the pathogen,
there is a small risk of the vaccine causing disease in individuals with
weakened immune systems, such as those with HIV/AIDS or
undergoing chemotherapy. Additionally, live attenuated vaccines must
be stored carefully, as they can lose their effectiveness if they are not
kept at the appropriate temperature or if they are exposed to certain
chemicals.
+ Examples of live attenuated vaccines include the measles, mumps, and
rubella (MMR) vaccine, the varicella (chickenpox) vaccine, the yellow
fever vaccine, and the oral polio vaccine (OPV). These vaccines have
been highly effective in preventing the spread of the diseases they
target and have contributed significantly to global public health efforts.

18. Progress towards the World wide eradication of polio :

19. Inactivated vaccines:
+ Inactivated vaccines are created by inactivating or killing the pathogen responsible for a
particular disease. The inactivation process is usually achieved by chemical or physical means
such as formalin, heat, or radiation.
+ The inactivated pathogen is then purified and formulated into a vaccine. Because the pathogen
is killed, it cannot replicate in the host and cause disease. However, it retains its antigenic
properties, which means it can still induce an immune response in the host.
+ Inactivated vaccines generally require multiple doses to achieve optimal immunity. This is
because the killed pathogen does not replicate and persist in the host, so the immune system
needs repeated exposure to build up a strong and long-lasting response. In some cases, booster
doses may be required years later to maintain immunity.

20. + Inactivated vaccines have some advantages over live attenuated
vaccines, which are created by weakening the pathogen. Because
inactivated vaccines do not contain live pathogens, they can be given
safely to immunocompromised individuals who may not be able to
receive live vaccines. Inactivated vaccines also do not cause disease in
the host, which is a concern with some live vaccines.
+ Examples of inactivated vaccines include the polio vaccine, which
contains inactivated poliovirus, the hepatitis A vaccine, which contains
inactivated hepatitis A virus, and the influenza vaccine, which contains
inactivated or fragmented influenza virus. Inactivated vaccines can also
be used for other diseases, such as rabies and pertussis.

21. Toxoid vaccine :
+ Toxins are produced by some bacteria and can cause significant damage to the
host’s tissues and organs. Toxoid vaccines are created by treating the bacterial
toxin with formalin or other chemicals to inactivate its toxic properties while
preserving its ability to stimulate an immune response.
+ When a toxoid vaccine is injected into a host, it stimulates the production of
antibodies that can recognize and neutralize the toxin. The antibodies are
specific to the toxin, not the bacterium that produces it.
+ Toxoid vaccines are typically given in multiple doses to build up immunity.
Booster doses may be required to maintain immunity over time.

22. + Examples of toxoid vaccines include the tetanus vaccine and the diphtheria
vaccine. The tetanus vaccine contains inactivated tetanus toxin, while the
diphtheria vaccine contains inactivated diphtheria toxin.
+ Toxoid vaccines have several advantages over other types of vaccines. They
are effective at preventing disease caused by bacterial toxins, which can be
very dangerous. They also do not contain live pathogens, so they can be given
safely to immunocompromised individuals. In addition, they do not cause the
disease they protect against, unlike some live vaccines.
+ Toxoid vaccines are an important tool in the prevention of bacterial diseases
caused by toxins.

23. Subunit vaccine:
+ Subunit vaccines are a type of subunit antigen-based vaccine that contain
purified components of the pathogen, rather than the entire microorganism.
This type of vaccine is often safer than traditional vaccines, as it does not
contain live or inactivated pathogens that can cause disease.
+ Subunit vaccines are often used for viruses and bacteria that have complex
structures, and for which it is difficult to produce effective whole-pathogen
vaccines. Subunit vaccines are typically composed of purified proteins, protein
fragments, or polysaccharides from the pathogen, which are chosen based on
their ability to elicit a strong immune response.

24. + There are several advantages of subunit vaccines over whole-pathogen vaccines. First, subunit
vaccines can be produced using recombinant DNA technology, which allows for large-scale
production of purified antigens. Second, subunit vaccines are generally safer than whole-pathogen
vaccines, as they do not contain live or inactivated pathogens that can cause disease. Third, subunit
vaccines are often more stable than whole-pathogen vaccines, as the purified antigens are less prone
to degradation.
+ However, there are also some disadvantages to subunit vaccines. One major disadvantage is that
purified antigens may not elicit as strong of an immune response as whole-pathogen vaccines, as they
lack many of the other components of the pathogen that can stimulate the immune system. To address
this issue, adjuvants are often added to subunit vaccines to enhance the immune response.
+ Examples of subunit vaccines include the human papillomavirus (HPV) vaccine, which contains
virus-like particles that mimic the structure of the virus, and the hepatitis B vaccine, which contains a
protein from the virus. In summary, subunit vaccines are a promising approach to vaccination that
offers several advantages over traditional whole-pathogen vaccines, but may require the use of
adjuvants to elicit a strong immune response.

25. Conjugate vaccine :
+ A conjugate vaccine is a type of vaccine that uses a carrier protein to link a
small molecule antigen to a larger molecule that can elicit a stronger immune
response. The conjugation of the antigen to the carrier protein makes it more
immunogenic and enables the immune system to recognize and respond to the
antigen more effectively.
+ The development of conjugate vaccines was driven by the need to protect
against encapsulated bacteria, which have polysaccharide capsules that are
poorly immunogenic in young children and immunocompromised individuals.
Polysaccharides are long chains of sugars that are highly variable and difficult
for the immune system to recognize as foreign. As a result, polysaccharide
antigens are not very effective in stimulating an immune response on their
own.

26. + To overcome this problem, researchers conjugate the polysaccharide
antigen to a protein carrier that is highly immunogenic, such as tetanus
toxoid or diphtheria toxoid. The conjugation of the antigen to the carrier
protein creates a hybrid molecule that is more easily recognized by the
immune system. This enhances the ability of the immune system to
generate an effective immune response against the polysaccharide antigen.
+ Conjugate vaccines have been highly effective in protecting against
bacterial infections, such as meningitis, pneumonia, and sepsis. Examples
of conjugate vaccines include the Haemophilus influenzae type b (Hib)
vaccine, the pneumococcal vaccine, and the meningococcal vaccine.
+ Overall, the conjugate vaccine technology has been a major advance in
vaccine development, enabling the creation of vaccines that are highly
effective in protecting against bacterial infections, especially in populations
that are most vulnerable to these infections.

27. A conjugate vaccine protects against Haemophilus
influenzae type b (Hib) :

28. DNA vaccine :
+ DNA vaccines are a type of vaccine that utilizes DNA as the immunizing
agent. The DNA vaccine encodes a gene for a specific antigen that is
expressed in vivo, leading to the production of the antigen by the host cells.
The antigen produced by the host cells is then presented to the immune
system, which generates an immune response against the antigen.
+ The DNA vaccine is constructed by cloning the gene for the antigen of
interest into a plasmid vector that can replicate in bacterial cells. The plasmid
is then purified and injected into the host, where it is taken up by host cells.
Once inside the host cells, the plasmid vector is transcribed and translated into
the antigen protein, which is then presented on the cell surface to the immune
system.

29. + DNA vaccines have several advantages over traditional vaccines. They are relatively easy to
produce and can be manufactured rapidly in response to emerging infectious diseases. They are
also stable and can be stored for extended periods of time without the need for refrigeration.
Additionally, DNA vaccines can induce both humoral and cellular immune responses, making
them a promising tool for the development of vaccines against a wide range of infectious
diseases, as well as cancer.
+ However, there are also some limitations to the use of DNA vaccines. One challenge is the
need for efficient delivery of the DNA into host cells. This can be achieved through various
methods, such as electroporation or the use of viral vectors, but these methods can be
expensive and may pose safety concerns. Another challenge is the potential for immune
tolerance to the antigen encoded by the DNA vaccine, which could limit the efficacy of the
vaccine over time.
+ Despite these challenges, DNA vaccines have shown promise in preclinical and clinical studies
and represent an exciting area of vaccine research and development.

30. Recombinant vaccine:
+ Recombinant vaccines are a type of vaccine that uses genetically engineered
proteins or virus-like particles (VLPs) as the immunogen. Recombinant
vaccines are produced by inserting the gene encoding the antigen of interest
into a vector, such as a plasmid or virus, which is then used to express the
antigen in a host cell. The resulting recombinant protein or VLP is then
purified and used as the immunizing agent.
+ One advantage of recombinant vaccines is that they can be produced in large
quantities using well-established biotechnology methods, which enables
rapid scaling up of production to meet the demand for the vaccine.
Additionally, recombinant vaccines are generally safe and well-tolerated,
since they do not contain live organisms.

31. + Recombinant vaccines have been developed against a variety of infectious
diseases, including hepatitis B, human papillomavirus (HPV), and influenza.
For example, the hepatitis B vaccine is produced using recombinant DNA
technology to express the viral surface antigen in yeast cells. The HPV
vaccine is produced using recombinant technology to express virus-like
particles that mimic the structure of the virus, but are non-infectious.
+ One challenge with recombinant vaccines is that they may not generate the
same level of immune response as a live attenuated vaccine, since they only
present a small part of the pathogen to the immune system. To overcome this
challenge, recombinant vaccines may be combined with adjuvants, which
are substances that enhance the immune response to the vaccine antigen.
+ Overall, recombinant vaccines represent a promising area of vaccine
research and development, as they offer a safe and effective alternative to
traditional vaccine approaches.

32. Production of vaccine using a
recombinant vaccinia vector :

33. Advantages of Vaccination:
+ It is used to induce long term humoral as well as cell-mediated immune response
against disease-causing pathogens.
+ Vaccines help in developing immunity against specific diseases.
+ It initiates a primary immune response, generating memory cells without making
a person ill. Later, if the same or very similar pathogens attack, a specific memory
cell already exists. They recognize the antigen and evoke secondary immune
response producing large numbers of antibodies that quickly overpower the
invaders.

34. + The immune system is strongest in adulthood that means infants;
children and elderly are particularly susceptible to a dangerous
infection. Vaccines strengthen their immune system and bypass this
risk.
+ The use of vaccines has been effective in developing resistance of
infection of microorganisms that cause cholera, diphtheria, measles,
mumps, whooping cough, rabies, smallpox, tetanus, typhoid, yellow
fever and poliomyelitis.
+ Vaccines can be a key tool in managing threat or pandemic situations
such as Covid-19 caused by a coronavirus.

37. Stability
Efficacy
Low cost
production
Safety
Effective
Long lived
immunity
Compatible
with local
Management
practices
Induces
mucosal &
humoral cell
mediated
response
VACCINE

38. + Reference:
KUBY Immunology 7th edition
https://www.mayoclinichealthsystem.org/hometown-
health/speaking-of-health/vaccine-safety-6-common-questions-
answered
Medical Microbiology and Immunology 2nd edition
Prescott’s Microbiology 12th Edition

39. Thank you