2. History of Vaccines
Variolation: Inoculation of smallpox into skin
(18th century). Mortality rate of 1% for variolation; 50%
mortality rate from smallpox.
Vaccine: a suspension of organisms or fractions of
organisms that is used to induced immunity
Vaccination:
- Inoculation of cowpox virus into skin (Jenner)
- Inoculation with rabies virus (Pasteur)
Herd Immunity
3. What is a Vaccine ?
A vaccine is the deliberate stimulation of adaptive immunity.
- Work by mimicking what happens during natural infection
without causing illness.
- Use altered versions of viruses or bacteria to trigger an
immune response.
- Are the most effective means of controlling infectious
diseases.
- Not only protect those who get them, but they also help
keep diseases at bay in the community; this is called herd
immunity
4. How Do Vaccines Work?
During natural infection:
- The immune system recognizes a pathogen as foreign and
makes an immune response to it. When a pathogen causes an
immune response, it is known as an antigen.
- Unfortunately, while the immune response is gaining strength,
the person is likely to be ill as the struggle between the pathogen
and the immune response is decided.
- One part of the immune response creates antibodies; this is
known as the antibody-mediated or humoral immune response.
- Antibodies are specific to antigens and have the ability to
remember them, so that if the same (or a very similar) antigen
tries to infect the person again, the immune response will be
stronger and faster thereby protecting the person from infection
—and illness.
5. How Do Vaccines Work ?
With a vaccine:
- The immune system recognizes the vaccine as foreign and
makes an immune response to it. The vaccine serves as an
antigen in that it causes the immune system to respond to it.
- One part of the immune response creates antibodies; this is
known as the antibody-mediated or humoral immune response.
- Antibodies are specific to the vaccine and have the ability to
remember it, so that if the vaccine or a very similar antigen is
seen again, the immune response will be stronger and faster
thereby protecting the person from infection.
- The main difference between a vaccine and natural infection is
that the person does not become ill while the immune system is
responding to the vaccine.
6. Vaccines changed medicine
Vaccines have literally transformed the landscape of
medicine over the course of the 20th century. Before
vaccines, parents in the United States could expect that every
year:
- Polio would paralyze 10,000 children.
- Rubella (German measles) would cause birth defects and
mental retardation in as many as 20,000 newborns.
- Measles would infect about 4 million children, killing 3,000.
- Diphtheria would be one of the most common causes of death
in school-aged children.
- A bacterium called Haemophilus influenzae type b (Hib) would
cause meningitis in 15,000 children, leaving many with
permanent brain damage.
- Pertussis (whooping cough) would kill thousands of infants.
7. Prevalence of polio (blue), measles (red), mumps (green),
and rubella (purple) in the US from 1950-2009, the black
lines indicate the introduction of a vaccine to protect
against each disease
Vaccine
Vaccine
Vaccine
8.
9. Types of Vaccines
1. Attenuated whole-agent vaccines
Living but weakened microbes.
Living microbes more closely mimic an actual infection.
Lifelong immunity is often achieved without booster
immunizations (effectiveness rate of 95% is not unusual).
Long term effectiveness probably occurs because the
attenuated microbe replicates in the body, increasing the
original dose and acting as a secondary (booster)
immunization.
Example: MMR (measles mumps and rubella) and TB
Risk: Weakened microbes can back-mutate to virulent
form
10. Types of Vaccines
2. Inactivated whole-agent vaccines
Use microbes that have been killed, usually by formalin or
phenol.
Examples of viruses: rabies, influenza, and Salk polio.
Examples of bacteria: pneumococcal pneumonia and
cholera.
3. Toxoids
Inactivated toxins
Tetanus and diphtheria
11. Types of Vaccines
4. Subunit vaccines
Use only antigenic fragments of a microorganism that
best stimulates the immune response.
Acellular: a vaccine consisting of antigenic parts
(example- pertussis)
Recombinant: uses recombinant DNA technology;
another microbes are programed to produce the
antigenic parts (example-hepatitis B).
12. Types of Vaccines
5. Conjugated Vaccine:
A vaccine consisting of the desired antigen and other
proteins.
Deals with poor immune response of children to vaccines
based on capsular polysaccharides (children typical to
respond to these antigens until 18-24 months).
Polysaccharides are combined with proteins (diptheria
toxoid) which gives significant protection (2 months).
Example: Haemophilus influenza type b
13. Types of Vaccines
6. Nucleic acid (DNA) vaccines
Plasmid DNA injected into muscle results in the production
of the protein antigen encoded on the DNA
Example: West Nile (for horses)
Clinical trials underway in humans
Many advantages for the less developed countries- gene
gun eliminate needles and syringes, requires no
refrigeration, and lower cost.
ANIMATION Vaccines: Types
14. Vaccines Used to Prevent Bacterial
Diseases
Disease Vaccine
Diphtheria Purified diphtheria toxoid
Meningococcal meningitis
Purified polysaccharide from
Neisseria meningitidis
Pertussis (whooping
cough)
Killed whole or acellular fragments of
Bordetella pertussis
Pneumococcal
pneumonia
Purified polysaccharide from 7
strains of Streptococcus pneumoniae
Tetanus Purified tetanus toxoid
Haemophilus influenza
type b meningitis
Polysaccharide from Haemophilus
influenzae type b conjugated with
protein to enhance effectiveness
16. Disease Vaccine
Rabies Killed virus
Hepatitis B Antigenic fragments of virus
Hepatitis A Inactivated virus
Smallpox Live vaccinia virus
Herpes zoster Attenuated virus
Human papillomavirus Antigenic fragments of virus
Vaccines Used to Prevent Bacterial
Diseases
17. Adults
Most adults don’t realize there are times when they, too,
need vaccines:
At certain ages
During pregnancy
Before travel
For occupational risks
When they have certain medical conditions
18. Vaccines for Adults
• Td/Tdap
• Human Papillomavirus (HPV)
• Varicella
• Herpes Zoster
• Measles, Mumps and Rubella
• Influenza
• Pneumococcal
• Hepatitis A
• Hepatitis B
• Meningococcus
28. R0: basic reproduction number; this number represents how many people in an
unprotected population one infected person could pass the disease along to
29.
30. Lecture prepared by
Mark Randa; Ph.D.
Watch the Following Video (HAS PROFANITY)
Penn & Teller's Bullshit – Vaccinations
https://www.youtube.com/watch?v=lhk7-5eBCrs
Anti-Vaccine Movement
31. The cause of the anti-vaccine
movement…
Many anti-vaccine parents mistakenly think that the scientific jury is out
In reality, there are no lingering questions, and it is important to recognize
that deviousness was involved in the mere suggestion of a link.
Not only was there never any evidence to support the notion that the
vaccination caused autism, the research that supposedly supported this
link was in fact wholly fabricated.
Unfortunately, the facts of this fraud get forgotten.
Discussions occasionally mention that the research has been
"discredited," but that description is in fact a massive understatement
32. The journal article…
In 1998, a British surgeon, Dr. Andrew Wakefield, published a
paper in The Lancet with 12 co-authors, reporting that the
measles, mumps and rubella (MMR) vaccine was associated with
"regressive autism" and colitis in 12 children.
The paper ignited and propelled anti-vaccine campaigns
throughout the world.
A journalist, Brian Deer, began investigating these children's
medical records and found that the paper's data were largely
fabricated.
33. The truth about the children…
Of the 11 children reported as having colitis, only 3 did, according to
the medical records.
Wakefield claimed that all 12 children were "previously normal," while
in fact 5 had developmental problems before receiving the vaccine.
Of the 9 with regressive autism, 3 had no autism at all.
Of the 8 children who reportedly developed symptoms only days after
receiving the vaccine -- which would be important in convincing a
court that the vaccine was to blame -- 6 took much longer, and for 2
it is not clear.
While Wakefield claimed 6 of the 12 children had all three features --
autism, colitis, and development of symptoms days after the
vaccination, in fact, 0 did.
34. And it gets worse…
It turns out that in 1994, a British-based anti-vaccine group,
JABS, claimed that the MMR vaccine causes brain damage
and other problems, and hired a lawyer, Richard Barr, who
then retained Wakefield, a surgeon.
Barr began sending Wakefield patients from the group, and
paid Wakefield over $700,000.
Most of the children's parents were associated with the anti-
vaccine group -- hardly an unbiased group.
35. What happened…
After Deer's investigation, Wakefield at first claimed
innocence, saying that the other authors had written the
final paper. In fact, he had written the paper, and the other
authors had signed on.
The General Medical Council began an investigation,
lasting 217 days, and concluded that Wakefield had
falsified the research.
The Lancet later retracted the paper, but only 12 years
after publishing it.
36.
37. Where is he now…
Wakefield's medical ambitions having been stifled, he is now
appearing as a speaker at conspiracy crank events, as well as
being the patron saint of anti-vaxxers everywhere.
In January 2012, Wakefield filed a defamation suit against Brian
Deer, the British Medical Journal and the BMJ's editor Fiona
Godlee personally.
The BMJ Group has noted that they stand by their article (and
pointedly call him "Mr. Wakefield" throughout the press release to
this effect). This suit was dismissed on jurisdictional grounds.