Vaccines Flashcards
Live natural viral vaccine
- Example of Jenner w/smallpox innoculation of child
- Used safer but antigenically similar cowpox to innoculate from human smallpox
- Jenner’s strategy cannot be applied to most pathogenic viruses b/c there is no “safe” counterpart
Live attenuated viral vaccines
- A live attenuated virus undergoes mutation so that it has reduced ability to grow in human cells (no longer pathogenic)
- Accomplished by growing the pathogenic viruses in cells from a non-human species and selecting for variants that grown in the non-human host, but are less fit to grow in the human host
Live attenuated viral vaccine examples
- Measles
- Mumps
- Sabin (polio) vaccine
- Yellow fever
- Live attenuated influenza (LAIV)- delivered intranasally
- Varicella (chicken pox)
- Rotavirus-delivered orally
Live attenuated vaccines advantages
- Better immunity b/c vaccine actually produces a limited infection
- Can spread the attenuated virus to contacts
Live attenuated vaccines disadvantages
- Can cause disease in immunosuppressed or immunodeficient individuals
*VAPP (vaccine assoc. paralytic polio)
*Varicella and MMR: vaccine contraindicated in pts w/known severe immunodeficiency
*LAIV: vaccine contraindicated in immunosuppressed pts., also in pregnant pts., children 2-4yo w/asthma and/or wheezing in last 12 months
*Rotavirus: precautions for altered immunocompetence
- Reversion to wild type or pathogenic virus
Killed viral vaccine
- Viral particles are chemicaly treated (formalin) or heated or irradiated
Killed viral vaccine examples
- Influenza vaccine
- Rabies vaccine
- Salk polio vaccine
Killed viral vaccines advantage
- Safe
- Does not cause disease
Killed viral vaccines disadvantages
- Must produce large amounts of virus
- Incomplete inactivation
- No replication of virus, therefore immunity may not be as “good”
Subunit vaccines
- Usually made via recombinant DNA technology and contain an antigenic surface structure that can induce neutralizing antibody and prevent infection
Subunit vaccine examples
- Hepatitis B vaccine
- HPV vaccines
Bacterial Vaccines
- Whole bacteria
- Toxins
- Capsular polysaccharides
- Live attenuated bacterial vaccines
Killed bacterial vaccines
- Bordetella pertussis
*when given w/tetanus toxoid and diptheria toxoid, the Bordetella organism causes stronger immune responses to the toxoids
*can induce bad reactions in some
- Use of “acellular” Bordetella preparation in newer vaccines
Toxoid vaccines
- In these vaccines, the toxin activity is destroyed, sometimes by formalin, but retains sufficient antigenic activity to protect against disease
Toxoid vaccine examples
- Tatanus
- Diptheria