vaccines Flashcards
live attenuated vaccine
- weakened form of virus/bug produced via repeated passage thru subculture
- pros: produce immune response similar to natural infection, usually only need 1 dose
- cons: severe reactions possible, can replicate so can mutate, fragile (require cold chain), response can be inhibited by circulating antibody
- ex: sabin, measles, MMR, varicella, zoster, BCG
inactivated vaccine
- whole killed organisms or fractional/subunit components
- pros: can’t replicate so no threat of disease
- cons: less effective, humoral response => require 3-5 doses/boosters, not inhibited by circulating antibody
- whole cell ex: salk, pertussis
- fractional ex: tetanus toxoid, flu, HPV, newer zoster
conjugated vaccines
- combine weak (polysaccharide or oligosaccharide) antigen with strong antigen (protein carrier) => T cell dependent B cell response (IgG)
- ex: pneumococcal, HiB
adjuvant
used to:
- increase magnitude of adaptive response to vaccine
- alter type of immune response (Th1 vs Th2, CD4 vs CD8, etc)
- increase T cell memory
- increase speed of response
recombinant viral vector vaccines
- viral vector expresses heterologous antigen and induces antigen-specific cellular immune response w/o requiring adjuvant
- ex: new Mtb vaccine, ebola
diseases eradicated (or eradicatable) with vaccine
- smallpox
- polio
- measles
- HiB (in US)
measles vaccine
- live virus
- pros: very effective, lifelong immunity
- cons: people think MMR causes autism (nope)
varicella vaccine
- live virus
- pros: very effective
zoster vaccine
- higher dose of varicella live virus vaccine
- has been replaced by a recombinant viral vector vaccine
polio vaccine
- salk = inactivated vaccine
- sabin = oral, live attenuated vaccine => allows person to person transmission but also risk of reversion to virulent strain
BCG
- live attenuated m. bovis
- cons: only protective 10-20 yrs and variable protection
pertussis vaccine
- DTP = whole cell vaccine => pretty effective after 3 doses, 5-10yrs, common adverse rxns
- TDaP = acellular subunit vaccine => less reactogenic (less adverse effects but maybe less durable tx)
tetanus toxoid vaccine
- formalin inactivated toxin
- pro: very effective after 3-4 doses + booster every 10 yrs
influenza vaccine
- trivalent influenza vaccine = inactivated subunit vaccine, injected, local rxns but few other side effects
- live attenuated vaccine = nasal route, associated with URI in adults and asthma flares in kids
HPV vaccine
- virus like particle = self-assembling structural polypeptide (capsomere)
- 9-valent and 4-valent
- 100% efficacy
recombinant zoster
- VZV glycoprotein + adjuvant
- pros: very effective
- cons: pain, fever/chills
new Mtb vaccine
- recombinant; 2 Mtb antigens + adjuvant
- 50% efficacy at 3 years
Ebola vaccine
- recombinant, replication competent VSV expressing ZEBOV glycoprotein
- pros: 100% efficacy
Pneumococcal PPV23 vaccine
- pure polysaccharide covering 23 strains
- ineffective in kids < 2 yrs
Pneumococcal PCV7/PCV13
- polysaccharide conjugated to non-toxic diphtheria toxin
- highly immunogenic in children/infants => more effective but more adverse rxns
HiB vaccine
- conjugate polysaccharide vaccine
- largely eliminated HiB meningitis in kids in the US
fractional vaccines
- subunit = isolated antigen (protein or polysaccharide)
- toxoid = inactivated toxins
typhoid vaccine
- capsular polysaccharide vaccine
