Vaccines
Mrs. Stewart
Adapted from: Project Lead The Way Making Vaccines powerpoint
Effective Vaccines
• Have low levels of side effects or toxicity.
Effective Vaccines
• Protect against exposure to wild forms of pathogen
Effective Vaccines
• Stimulate both types of immune responses:
1. an antibody/humoral response• B Cells
2. a cellular/cell-mediated response• T Cells
Effective Vaccines
• Have long term, lasting effects that produce immunological memory.
Effective Vaccines
• Should not require numerous doses or boosters
Effective Vaccines
• Are inexpensive
• Have a long shelf life
• Are easy to administer.
Routes of Administration
• The majority of vaccines are administered by injection– Subcutaneous– Intramuscular– Intradermal
• Oral vaccines are available for only a few diseases
Administration Routes
Live, attenuated (weakened) cells (viruses)
– Vaccines are longer-lasting and require fewer boosters
– However, the disease agent could mutate back to pathogenic strain
– Harder to make this type for bacteria – usu. viruses
– Example: MMR, Varicella zoster
Killed whole cells or inactivated viruses
– Even though they are harmless, they still contain recognizable antigens on their surface
– Because the microbe does not multiply, a weaker immune response is stimulated vs. live vaccines
– larger doses and more boosters are required.
– Example: Polio virus
Toxoid vaccines
– A purified toxin produced by the pathogen is changed into a toxoid and used to elicit immune response.
– Example: DTaP• Diptheria,
Tetanus & acellular Pertussis
Subunit Vaccines
• Subunit vaccines contain just the antigens of the microbe that best stimulate the immune system.
• Antigens that have been separated from the rest of the microbe
• Examples: Hepatitis B, Gardasil,
Genetically engineered or Naked DNA Vaccine
– Genes for microbial antigens are inserted into a plasmid vector and are cloned in appropriate hosts.
– The resultant protein product is used to provoke immune system.
DNA vaccines
– These vaccines contain all or part of the pathogen DNA, which is used to “infect” a recipient’s cells.
Herd Immunity• More individuals that are
immune decreases the incidence of the disease and the occurrence of the pathogen.
• With greater numbers immunized, it is less likely that an unimmunized person will encounter the pathogen.
• Mass vaccination confers indirect protection for those who do not receive the vaccine resulting in “herd immunity”.
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