Vaccines Flashcards
What is a vaccine?
biological suspension of weakened or killed pathogens (bacteria/virus) or their components
Goal of administering vaccines
Produce artificially - acquired, active immunity to a specific disease
Immunization
process by which a person becomes protected from a disease; vaccines cause immunization
Vaccine primary response
“1st - vaccination administered
- B lymphocyte detects AG on surface of vaccine organisms
- B lymphocyte multiplies/clones
- Cloned B lymphocytes differentiate to plasma/memory B cells
- Plasma cells secrete ABs -> bind and disable organism of vaccine “
Vaccine secondary response
“1st - Exposure to real infective organism
- memory b cells recognize organism
- memory b cells multiple rapidly
- memory b cells develop into plasma
- plasma cells produce a larger number of ABs, which are able to quickly bind to and activate the infecting org “
Classic vaccine characteristics
”- Live, attenuated (or weakened)
- Nonreplicating (or inactivated)
- Subunit (purified antigen); including conjugate vaccines
- Toxoid (inactivated toxins) “
Synthetic vaccine characteristics
”
- Recombinant
- DNA”
Advantages of live, Attenuated vaccines
“Closest thing to a natural infection (replicate at low level in the host; induce both humoral and cell-mediated immunity)
Often provide lifelong immunity with only 1 or 2 doses
Easy to create for viruses (small genome allows for better control)”
Advantages / Disadvantages / Examples of activated vaccines
“Advantages:
- Closest thing to a natural infection (replicate at low level in the host; induce both humoral and cell-mediated immunity)
- Often provide lifelong immunity with only 1 or 2 doses
- Easy to create for viruses (small genome allows for better control)
Disadvantages:
- Possibility that the attenuated microbe could revert to a virulent form
- Not everyone can safely receive vaccine; immunocompromised
- Need to be refrigerated
Examples:
- Rotavirus
- Herpes Zoster/Varicella
- Measles/Mumps/Rubella”
Disadvantages of live, Attenuated vaccines
“Possibility that the attenuated microbe could revert to a virulent form
Not everyone can safely receive vaccine; immunocompromised
Need to be refrigerated”
Advantages / Disadvantages / Examples of Inactivated vaccines
“Advantages:
- Stable (do not require refrigeration)
- More safe than live vaccines (do not mutate back to disease-causing state)
Disadvantages:
- Stimulate a weaker immune response than live vaccines
- May take additional doses or booster shots to maintain a person’s immunity
Examples:
- Inactivated polio virus
- Influenza”
Advantages / Disadvantages / Examples of Subunit/Conjugate vaccines
Advantages:
- Chance of adverse reaction is low (only uses the antigen or specific part of the antigen to stimulate response)
- Excellent stability
- No live components thus no risk of inducing disease
Disadvantages:
- Difficult and time-consuming to identify the best antigens
- No guarantee that memory will form for future responses
Examples:
-Hepatitis B (hepatitis B virus surface antigen)
Conjugate vaccines
When bacteria produce a polysaccharide coat, it disguises the bacterium’s antigen thus no immune response
To circumvent this, the polysaccharide is bound to a carrier protein that can induce a longer-term protective response
Allowed vaccines to be produced by encapsulated organisms
Examples: Haemophilus influenzae type b; and pneumococcal
Advantages / Disadvantages / Examples of Toxoid vaccines
Advantages:
- Used when the bacterial toxin is the main cause of the illness; the toxins are inactivated thus safe
- Stable, less susceptible to environmental conditions
Disadvantages:
- Difficult and time-consuming to identify the best antigens
- May require several doses and usually need an adjuvant
- Not highly immunogenic
- Adverse reaction: anaphylaxis (1-6 per million)
Examples:
- Tetanus toxoid
- Diphtheria toxoid”
DNA Vaccines
“Stimulates a strong cellular response; utilize the microbes genetic material that code for the antigens
Relatively easy and inexpensive in design”
