Lecture prepared by

Mark Randa; Ph.D.

Vaccines

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

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

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.

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.

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.

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

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

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

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).

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

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

Vaccines Used to Prevent Bacterial Diseases

Disease VaccineDiphtheria 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

Disease Vaccine

Influenza Injected vaccine, inactivated virus (nasally administered: attenuated virus)

Measles Attenuated virus

Mumps Attenuated virus

Rubella Attenuated virus

Chickenpox Attenuated virus

Poliomyelitis Killed virus

Vaccines Used to Prevent Bacterial Diseases

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

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

Vaccines for Adults

• Td/Tdap

• Human Papillomavirus (HPV)

• Varicella

• Herpes Zoster

• Measles, Mumps and Rubella

• Influenza

• Pneumococcal

• Hepatitis A

• Hepatitis B

• Meningococcus

Lecture prepared by

Mark Randa; Ph.D.

Herd Immunity

No one vaccinated…

Some of the population vaccinated…

Most of the population vaccinated…

R0: basic reproduction number; this number represents how many people in an unprotected population one infected person could pass the disease along to

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

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

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.

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.

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.

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.

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.