Principles of Vaccination Flashcards
what is variolation
small amounts of lesion material inoculated into skin, reduced deaths from small pox from 1/4 to 1/100
how did vaccination with cowpox pustule material protect people from smallpox virus infection?
since cowpox and smallpox viruses share some surface antigens, immunization with cowpox induces Ab against the similar cowpox surface Ag. then, these cowpox Ab bind and neutralize smallpox virus
3 reasons why people don’t vaccinate
- distrust in vaccines
- cost
- supply and availability
antivaxxer reasons for being antivaxxer
- think they are not needed and fraud
- full of toxic additives
- health measures are sufficient (look our disease diminished without vaccines)
- drug companies are evil
describe mercury in vaccine formulation
there was low doses of thimerosal as preservatives until 2001, and there is no evidence of harm or link to autism. more of this in 3oz can of tuna
how is thimerosal broken down
ethylmercury which is cleared quickly, reducing any chance of harm to minimum
what is more toxic than thimerosal WAS in vaccines
methylmercury which is in some foods and fish and breastmilk, is toxic in high levels and it is NOT IN VACCINES
tell me about formaldehyde in vaccines
formaldehyde is used to inactivate viruses or bacterial toxins, and is washed out before production. trace amounts may remain, but there is more formaldehyde in antihistamines, cough drops, mouthwash, carpet, cosmetics, paint, markers, automobile exhaust
why are death rates for infectious diseases decreasing?
HERD IMMUNITY
what is herd immunity
if the majority of a population is immune to an agent, the chance of a susceptible individual contracting from an infected person is very low
why are outbreaks a thing then?
decrease in herd immunity
what vaccines are given at birth?
Hep B
what vaccines are given between 1-2 mon?
Hep B
what vaccines are given 3 times between 2-6 months?
- RV
- DTAP
- Hib
- PCV13
- IPV
how many doses of DTAP?
5
how many doses of IPV?
4
how many doses RV?
3
how many Hib?
4
how many PCV
4
how many MMR?
2
how many varicella?
2
how many Hep A?
1 (2 in adults)
what vaccines must wait until at least 6 months to give?
- 3rd dose Hep B
- 3rd dose IPV
- flu
what vaccines do you have to wait until 1 year
- MMR
- varicella
- Hep A
vaccine schedule for Hep B
birth, 1-2 mo after, 6 mo after initial
vaccine schedule for RV
1 dose 2 mo, 2 dose 2 month later, 3 dose 2 month later
vaccine schedule for DTAP
3 doses 2 month apart starting at 2 months, 4th dose at 15months, last dose 4-6years
vaccine schedule for Hib
4 doses 2 month apart starting at 2 months
PCV13 schedule
4 doses 2 month apart starting at 2 months
IPV schedule
2 doses at 2 and 4 months, 3rd dose between 6-18months, last dose 4-6 years old
MMR and varicella schedule
1 dose at 12mo, 2nd 4-6yo
when can baby get Hep A vaccine?
12 months
why do we wait to give some vaccines until 12 months old
persistent circulating maternal Ig may bind to Ag that was delivered by the vaccine, and block adequate immune activation
why are some vaccines given multiple times?
formulation of vaccine itself may provide limited amt of Ag to mount an immune response, plus multiple doses ensure adequate immunity generated by different strains
what are live attenuated vaccines?
microbes cultured in an organism that it isn’t supposed to be in, thereby weakening it, aka promote loss ability to cause significant disease (decreased virulence)
which vaccines are live attenuated?
- MMR
- rotavirus
- polio (oral sabin - not used)
- Tb (not used)
- varicella
- yellow fever
advantages of live attenuated
- strong immune response bc can replicate (CTL and HLA class I action)
- lifelong memory (memory cells)
- few doses
disadvantages of live attenuated
- needs to be refrigerated
- may mutate to virulent form (highly unlikely)
- immunosuppressed cannot get
what is inactivated/killed vaccine?
microbes inactivated by heat or formaldehyde so pathogen can induce immunity but cannot replicate within the host
which vaccines are inactivated?
- Hep A
- cholera
- flu
- plague
- polio (salk used)
- rabies
advantages of inactivated vaccines?
- stable storage (doesnt need to be refrigerated)
- safer than live attenuated
- safe for immunosuppressed
disadvantage of inactivated vaccines?
- weaker immune response (mostly Ig production)
2. more doses to induce effective immunity bc it doesn’t replicate
what are subunit (acellular) vaccines?
components of infectious agent are used in formulation (toxoid, capsular polysaccharides, recombinant proteins)
what occurs when vaccinated with a toxoid?
neutralizing Ig
which are toxoid vaccines?
tetanus and diptheria (they need to be combined with something to stimulate dendritic cell maturation)
what occurs when vaccinated with capsular polysaccharides?
opsonizing Ig
which are capsular polysaccharide vaccines?
PCV23, neisseria meningitidis
what occurs when vaccinated with recombinant proteins?
neutralizing and or opsonizing Ig
which is recombinant protein vaccine?
Hep B
which vaccines are subunit/acellular?
- DTaP
- Hep B
- streptococcus pneumoniae (PCV23)
advantages of subunit?
- immune system targeted to recognize toxin
- specific Ag used so low chance of adverse reaction
- safe for immunosuppressed patients
disadvantages of subunit?
- require adjuvant
2. difficult to produce
what are conjugate vaccines?
vaccines against non-protein Ag (opsonizing IgG directed against polysaccharide capsules)
most effective defense against bacteria that have polysaccharide capsules?
opsonization of capsule by Ig
what occurs if you conjugate bacterial polysachharide to protein carrier?
TFH responds but leads to B cell memory response, not T cell memory.
describe what occurs when conjugated vaccine enters the system
- BCR can bind polysaccharide to trigger B cell activation
- DC binds to conjugate vaccine via binding to the toxoid
- DC processes toxoid and displays on MHC II to activate TFH cells
- BCR signaling commenses, conjugate vaccine is endocytosed and digested.
- toxoid peptides loaded on MHC II
- MHC II peptides engage TCR of activated pre-TFH cells
- B cells receive IL-2,IL-4, IL-5 to initiate B cell proliferation and CD40 ligation to induce AID for somatic hypermutation
- pre-TFH turn into TFH and migrate into germinal center to engage GC B cells and do PC differentiation and B cell memory generation
- PC produce Ig specific for capsule Ag
- TFH interaction ensures that LLPC and B memory cells develop = long term protection from bacteria thorugh capsule Ag specific Ig
why is it important that TFH engage with GC B cells after vaccine
aid in PC differentiation and B cell memory generation, and ensures that they develop
goal of conjugated vaccines
provoke a B cell response to a carb, not a T cell response to a peptide. toxoid is used to activate TFH so that B cells become memory and make Ig specific for toxoid
what is adjuvant
substances that enhance immunogenicity of Ag by establishing a state of inflammation
which vaccines contain purified Ag that are not strong immunogens?
subunit and conjugate vaccines, so they need adjuvants
what is a good adjuvant for Ig production?
super small amounts of aluminum salts (alum)
what do adjuvants do?
promote increased Ag uptaek and processing, MHC class II and CD40 and CD86 expression to mature the APC/DC
what is CD86
signal 2 costimulation
