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”
Recombinant vector vaccines
“Use an attenuated virus or bacterium (“vector”) to introduce microbial DNA to cells of the body
Closely mimic a natural infections, thus strong immune response”
