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Biotechnology and Global Health > Lecture 8: Vaccines > Flashcards

Lecture 8: Vaccines Flashcards

1
Q

What is immunization?

A

Process by which an individual’s immune system becomes fortified against an immunogen

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2
Q

What are the 2 types of immunization?

A
  • Passive: transient

- Active: long term

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3
Q

How is passive immunization accomplished?

A
  • Maternal antibodies

- Monoclonal antibodies and antitoxins

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4
Q

What is vaccination?

A

Practice of artificially inducing immunity

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5
Q

What is the goal of vaccination?

A

Immunological memory - to stimulate both arms of the adaptive immune system (humoral and cell-mediated)

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6
Q

What should a vaccine have?

A

The maximum effect at a minimal danger

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7
Q

What are the 5 types of vaccines discussed in class?

A
  • Inactivated or “killed”
  • Live, attenuated
  • Subunit and conjugate
  • Recombinant vector
  • DNA
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8
Q

How are inactivated or “killed” vaccines made?

A

By heating or chemically treating the pathogen, however they must maintain the physical structure.

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9
Q

What are the pros and cons for an inactivated or “killed” vaccine?

A

Pro

  • Non-infectious
  • Stabile
  • Good shelf life
  • Easy to transport
  • Assurances of completely killed

Con

  • Less effective at activating cell-mediated response
  • Requires boosters

Ex. Influenza, plague, cholera, Hep A, rabies

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10
Q

What are adjuvants?

A

Substances incorporated along with antigen in a vaccine.

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11
Q

What is the role of adjuvants?

A

They decrease the amount of antigen necessary to induce an immune response.

  • Prolong antigen persistence
  • Enhance costimulatory signals
  • Increase local inflammation
  • Stimulate lymphocyte proliferation
  • Enhance size of antigen for phagocytosis
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12
Q

How are live, attenuated vaccines made?

A

The pathogen is weakened due to prolonged growth in abnormal conditions. Conditions can include different temperature, pH, host. They can also be genetically engineered.

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13
Q

What are the pros and cons for a live, attenuated vaccine?

A

Pros

  • Strong immune response
  • Activates both arms of the adaptive immune response

Cons

  • Possibility of reversion
  • Complications of over-response
  • Cannot use in immunocompromised
  • Storage concerns
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14
Q

How are subunit vaccines made?

A

They are specific, purifies macromolecules such as inactivated exotoxins that produce toxoids. Can also include polusaccharides and glycoproteins

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15
Q

What are the pros and cons for subunit vaccines?

A

Pros

  • Stimulate humoral response
  • Minimal danger of infection
  • Stable/good shelf life
  • Portable

Cons

  • Usually requires a booster
  • Does not stimulate cell-mediated immunity
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16
Q

How are conjugate vaccines made?

A

A subunit from a target pathogen is irreversibly bound in a ‘conjugate’ with bacterial proteins. The B-cell will engulf and present epitopes from the vaccine. The conjugate elicits an enhances immune response.

17
Q

What are the pros and cons for conjugate vaccines?

A

Pros
- Stimulates both humoral and cell-mediated

Cons
- More complex

18
Q

How is a recombinant vector vaccine made?

A

Exogenous genes from the pathogen are inserted into a non-virulent virus or bacterium

19
Q

What are the pros and cons for conjugate vaccines?

A

Pros

  • Stimulated both humoral and cell-mediated response
  • No real danger of infection

Con
- Pre-existing immunity to carrier might block effect (must use different carrier for booster)

20
Q

How are DNA vaccines made?

A

Pathogen plasmid DNA with gold particle injected into the muscle through a gene gun. Cells will take up the DNA, incorporate it and begin o form proteins of antigens.

21
Q

What are the pros and cons for DNA vaccines?

A

Pros

  • Both cell-mediated and humoral immunity
  • Prolonged antigen expression renders significant immunological memory
  • Easier storage that live attenuated

Cons

  • Still experimental
  • Deliver is non-trivial
22
Q

How are vaccines tested? 3 different ways

A
  • Laboratory testing (vaccine dev. & cell culture)
  • Animal model (animals must be susceptible to pathogen and show same symptoms as humans)
  • Clinical trials in humans
23
Q

Explain the components of a Phase I clinical trial.

A
  • Small number of participants (20-100)
  • Determine vaccine dosage
  • Evaluate for side effects
  • FDA must approve vaccine as an Investigational New Drug (IND)
24
Q

Explain the components of a Phase II clinical trial.

A
  • Larger number of volunteers (>200)
  • last few months - years
  • Controlled study (control vs. placebo (or existing vaccine))
  • End Points: Safety & Effectiveness
25
Q

Explain the components of a Phase II clinical trial.

A
  • Large number of volunteers (100s - 1000s)
  • RCT (control vs. placebo (or existing vaccine))
  • How you get efficafcy
26
Q

How is efficacy measured?

A

Efficacy = [(ARU-ARV)/ARV] * 100

27
Q

What is effectiveness?

A

It is the “real world” performance.

Important to note 1-2 of every 20 people immunized will not have an adequate immune response

28
Q

What is herd immunity?

A

Because vaccinated people have antibodies against a pathogen, they will protect those who are unvaccinated. (75-95% of coverage is needed)

29
Q

Who decides vaccine recommendations?

A

HD and expert physician organizations

  • When should vaccines be used
  • Who should receive it
  • Weight the risks and benefits of the vaccine and costs of vaccination
30
Q

What is the legislation regarding vaccination?

A 
States decide which vaccines are required by law, but all 50 states have school immunization laws.
Can be exempted due to...
- Medical reasons
- Religious reason
- Philosophical reasons
31
Q

What are the challenges for vaccine development in the developed world?

A
  • Cost (Need facilities, regulation, litigation)

- Market Size (Usually purchased once, >50% bough by public sector)

32
Q

What are the challenges for vaccine development in the developing world?

A
  • Transportation (must be heat stable/UV protected)
  • Cost (single dose effective)
  • Update in mucosal membranes
  • Syringe use
  • Trained health workers
33
Q

How to address the issue with heat/freeze/UV with vaccines?

A
  • Temperature-sensitive and UV sensitive labels
  • Lower-cost solar refrigerators
  • Phage-change material used in vaccine carriers prevent the freezing of vaccines
  • Thermo-stable vaccines
34
Q

How to address the issue with syringe use/healthcare workers with vaccines?

A
  • Use one-time use or disposable syringes
  • Need for a needle-free delivery (jet injectors)
  • Intradermal adapter (standardized injection depth/angle, less human error)
35
Q

What is antigenic drift?

A

The gradual, spontaneous, minor change. Can include point mutations.

36
Q

What is antigenic shift?

A

A sudden and unique change. Can be cause by reassortment.

Biotechnology and Global Health (10 decks)

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