Vaccines Flashcards
Phases in clinical testing of vaccine
Phase I, II, III
What are the steps after clinical trial?
I) wait for approval from FDA or other organizations
II) scale up production of vaccine
III) adminster vaccine —> develop immunity
Examples of non-live vaccines
Influenza, HBV, varicella, Covid
Types of influenza with medical attention
I) influenza A
II) influenza B
How long does influenza incubate for?
1-5 days
Examples of complications from influenza
Pneumonia, myocarditis
What are symptoms of influenza similar to?
Other upper respiratory infections
Ways develop to produce influenza vaccine
I) inactivated vaccines
II) live attenuated vaccines
III) recombinant HA vaccines
How does recombinant HA vaccine work?
Engineer baculovirus to express recombinant HA
How are influenza vaccines developed in 1936?
Embryonated eggs
Who proposed to use embryonated eggs for flu vaccine?
Jonas Salk, Thomas Francis Jr
How many flu viruses arae in one flu vaccine
Three or four
(Usually 2 from influenza A and 1/2 from influenza B)
Why should we get flu shot?
lower the risk of getting myocardial infarction if infected by influenza
Which age group has higher risk for HBV?
infants, child from 1 to 5 y/o
How was the first HBV vaccine developed?
I) obtain antigen directly infected ppl
II) used diff methods to deactivate and filter infectious HBV
III) able to isolate secreted HBV S antigen
When was the HBV S antigen found? And by who?
1963, Dr. Baruch Blumberg
Better method for HBV vaccine
I) express HBV S antigen on yeast
II) they then self assmeble into particles
III) these particles released from yeast and purified
Incubation period for HBV vaccine (Newer one)
6w to 6 months
How come HBV vaccine able to provide such long lasting protection?
Long incubation period
—> able to generated antibody levels above level needed for protection
What is the form of first varicella zoster virus vaccine?
Live attenuated
Why is the first vaccine for zoster not ideal?
cannot be used for immunocompromised individuals
Groups at risk of zoster
I) elderly
II) immunocompromised ones
Better version of VZV vaccine
Reombinant vaccine for shingles
How is newer of VZV vaccine administered?
Through muscle
What mounts the immune response in shringles vaccine?
Purified VZV group E
Why is group E in VZV chosen to use in vaccine
Most abundant on surface of VZV and cells infected by VZV
What is the immune response mounted after getting this shingles vaccine
Memory T cells and antibody specific to gr E
—> for ppl who have pre-existing immunity to VZV
Ways to deliver S antigen for covid vaccine
I) mRNA
II) adenovirus vector that express S antigen
III) deliver S antigen itself
How come covid vaccine took such little time to develop?
Lots of money used
—> government funding allow each phase to proceed immediately after previous one
How come mRNA vaccines is a good way to present antigens?
Less side effects
(Can be used for immunocompromised ppl)
What is used to check the efficacy of vaccines against new virus variants?
Plaque reduction neutralization test
What to do if neutralizing antibody levels fall over time?
Can do booster shots
—> increase amount of antibodies
Immune components important for Covid vaccine
Memory B cells generated (high affinity)
—> diverisity of them allow better response to variants (hybrid immunity)
What is a vaccine?
Biological product that induce an immune response that confers protection against infection or disease when you are subsequently exposed to pathogen
Two ways that vaccine lead to protection against a virus
I) mechanistic (specific, functional immune mechanism)
II) non-mechanism (has statistical relationship with protection)
Example of mechanistic protection
Anti toxin antibodies for tetanus vaccine
Example of non-mechanistic protection from vaccine
Anti-S IgG for HBV
Difference between live and non-live vacines
I) Components: live has either attenuated virus or recombinant that express immunogenic proteins
—> non live have purified proteins or inactivated wt virions
II) infection: only occurs in live vaccine
III) induced immune reponse: both form antibody against virus, but only live vaccine have cell-mediated immunity
Examples of live vaccines
Vaccinia, Polio, Ebola
How is variola transmitted?
Airborne, droplet, contact
Where does variola virus replicate?
Cytoplasm, different from other DNA viruses that do it inside nucleus
Symptoms of smallpox
Headache, rash, vomit, prostration
In how many places is variola virus found today?
2
What did edward jenner do for smallpox?
Did variolation by getting samples from cowpox patients
—> inject into healthy ppl and see if it can protect against small pox
What is variolation
Dried scabs scratched into arm
What is the method preferred for most countries for variola?
Vaccination, variolation banned
When was smallpox declared eradicated?
1980
What is the origin for vaccine of smallpox?
Cowpox, maybe horsepox virus?? (Still unsure)
What is the beaugency lymph?
The source of cowpox used in many smallpox vaccines
Why horsepox might be origin for vaccinia?
I) cannot be identified from infection with vaccinia or cowpox
II) low titers of infection in human
—> no signs of disease
Are we getting closer to figure out mystery of vaccinia origin?
Not rlly
—> modern sequencing: one Horsepox strain sharing common origin with all vaccinia strains
(That horsepox resembles some smallpox vaccines)
Forms of polio vaccines
I) inactivated virions
II) Oral
What is in inactivated virions for polio vaccine?
Wt virions (Type 1,3) treated with formalin to crosslink protein
How does inactivated polio vaccine protects individual?
antibody binds to polio
—> unable to infect cells in CNS
Key mutation acquired in oral vaccine for polio?
Affect IRES
—> poor replication of virus
—> can stimulate sufficient levels of humoral and cell-mediated immunity
How does oral vaccine for polio mount immune reponse?
Polio virus infect cells in intestine
-> make progeny virus excreted in stool
How does oral vaccine for polio protect ppl against the virus?
I) for progeny virus, only replicate inefficiently that infected cells are destroyed in CNS
II) if wildtype contacted, mucosal antibody binds to virus to prevent infection
Who invented inactivated virions for polio vaccine
Salk
Who invested oral polio vaccine
Sabin
How is oral vaccine for polio generated
Attenuation through lots of passages (for each strain: 1 to 3)
How would someone get vaccine derived polio?
If unvaccinated individuals in contact with ppl taking oral polio vaccine
How does canadian made ebola vaccine work?
VSV expressing ebola glycoprotein
Efficacy of canadian made ebola vaccine
95 to 100% in west africa
