Vaccines Flashcards
Why are vaccines so good?
- they are cheap
- they prevent illness
What does our immune system have that is beneficial, especially with vaccines?
A memory!
when we get exposed to an illness, the memory stored in our immune system allows us to not get as sick
What do illnesses + viruses do to our bodies?
they cause scarring in the respiratory system (wear + tear)
What is a vaccine?
it is a FAKE illness
- it manipulates the immune system and helps memory formation of an illness without getting it
What is a limitation of the immune system?
it is selective but very slow, there is a lag time and a ramp-up period (2-3 days) where an illness brews
we want to avoid this, so copies are made: ANTIBODIES
What are antibodies?
recognition devices: Y-shaped + sticky ends
- 3D shape
what is another name for antibodies?
immunoglobulin
2 kinds: IgD, IgM
What is the part of a virus that an antibody notice’s called?
epitope
What cells are antibodies found in?
B-cells
B-cells:
They carry antibodies, each cell carries a different one
- a small amount of them are stored but an immune response will trigger the replication of the one that is needed - and these target the invaders
- These become memory cells after infection
what percentage of B cells are in a new born vs someone who has gotten sick as they get older?
<5% vs. >50%
Where do viruses live in our body?
inside our cells - hard to access with antibodies
What system does the body use to get rid of viruses?
they use T-cells which carry receptors (carry information)
if T-cells make a sandwich with the MHC receptor the protein will be in between and the T cell will recognize + get rid of the infected cell
2 types of T-cells - what happens when they communicate?
Killer T-cells
Helper T-cells (cross check)
they look for infected cells
they communicate together, and the killer T cell will send a signal to the infected signal which tells it to die, apoptosis
What receptor is found on the outside of every cell? what does it do?
MHC
- collects fragments of proteins that are cut up and are displayed in the MCH receptors, if the protein comes from a human protein - good/ if the protein is a virus protein the MHC receptor will help trigger the process of cleaning out the cell
with this process of killing viruses, how do vaccines help?
they trick the immune system into thinking there’s a virus, memory cells will be formed in the process and will prevent future illness later on
what was a practice to protect against small pox in many cultures?
Variolation: you collect some of the puss from someone who has it and injects it into small children, so those that recover would be protected later on
Small Pox
20-40% mortality rate
if you survived you had a high probability of being disfigured 70-80%- scars
What is Edward Jenner do?
he noticed that some people didn’t get smallpox, people who worked closely with cows didn’t get it (milkmaid), and they contracted a disease from cows (cowpox) - maybe getting infected with it protected against smallpox
experiment:
- infected children with cowpox and then smallpox and they didn’t get it
- this was unique to smallpox only
VACCINATION!! - much better, people didn’t die with a “fake” virus
when was smallpox eradicated from developing countries? global program? last case?
1950’s, 1966, 1977
when did we stop vaccinating for smallpox in Canada? what identifies if you had the vaccine?
1972
a scar created by the needle - some countries still do it
Anthrax
cattle disease - dangerous is humans come in contact
What did Louis Pasteur discover?
you can weaken bacteria by heating them “attenuated” - only causes a mild infection
one injection did not stimulate a strong immune reaction but a second “booster shot” helped and produced more memory cells
Booster shots
used with attenuated or dead viruses, there is a threshold for the amount required he immunity, and booster shots surpass that
Polio
1% is paralytic - paralysis including lungs (iron lung was used to help)
many epidemics in the 1900’s
What president was a survivor of polio?
Rosevelt
Salk Vaccine:
used for polio
- uses a dead virus - very effective
- injection + booster
1.4M children injected in schools
there was an incident with a defected batch - 11 deaths
Sabin vaccine
- used live virus - but weakened
- orally given + no booster
in russia:
- 77M vaccinated
- highly effective
- small risk of polio
- 1 case in ever 1 million
adopted by most countries
how many cases of polio in the entire world in 2003? when did it bounce back?
fewer than 300
2009 there were more than 1600
- due to politics - vaccines
cases have dropped 99% since then
Influenza
seasonal colds
- infects 5-15% of a population
- new virus every year
most are not dangerous but very young and very old are exceptions
when were occasional severe influenza pandemics?
1918, 1957, 1968
Flu vaccine
- uses dead virus
- new one every year
doesn’t cause disease, used for decades, low incidence of side effects (less than 0.01%)
- important to vaccinate early- takes 21 days for full immunity
Why low % of effectiveness?
because researchers have to anticipate which strains will be prevalent
- manufacture starts in the spring, flu season is in the fall
- educated guess on which will be important!
flu season starts in October and vaccines are given late November, the 21 day immunity will go into December
doesn’t mean its not good, but seasonally there are errors
Is the shot still worth to get?
Yes, because even if you get the wrong type, maybe the next year or 2 that will come out and you’ll be protected for that one
Main side effects of flu vaccines?
egg allergy
why do the benefits of vaccines get noticed?
because nothing happens, that’s the benefit
but side effects are seen, so the negative is more focused on
Jenners time
opposition to vaccination
Vaccines and autism
NO LINK
- the doctrine of signatures, and autism shows later, but they got vaccines earlier so it seems like a link… BUT NO
Wakefield study
appeared to back up autism claims
FRAUD
H1N1 panic
worry about the preservatives in the flu vaccine
- Thimerosal: SAFE
- but contains mercury which affects the brain and autism affects the brain… but no link
adjuvants
worry during H1N1
- reduce the need for booster shots - stronger immune response
- one shot and done
what adjuvant was most used in early vaccines
Alum
- rock/stone dissolved in water
more recent adjuvant
lipids: discovered in 1970’s
- fats and oils
Gulf war Syndrome
Squalene was blamed, in military vaccines - many got sick
but… there was no squalene in military vaccines - snowballed to new conspiracies
squalene in the body
our body makes it regularly - human metabolite
- it is safe - no difference in vaccine with squalene and same vaccine without
side effects of the vaccine:
- swelling, fever (good), allergic reaction (rare), disease (rare)
Why vaccinate if a country is disease-free?
the unvaccinated keep the disease alive, and travellers exist, as long as they’re around we must protect ourselves
Herd immunity
certain % of pop that is vaccinated to keep up that protection, has to be maintained as long as the disease exists
cervical cancer
viral disease
found in women who are sexually active in 1842
the infection of general warts caused the concern
HPV virus was linked to cancer in 1970’s
more than 200 types - only a few cause cancer
- destroy p53
Virus structure + recombinant vaccine
Capsid with DNA material inside
we can get an immune response with empty virus capsid
- An empty container is enough to give you protection
- Don’t need the whole virus, just part of one of the proteins
- not virus, its a piece of a piece of a virus into yeast
Guardasil
made using recombinant yeast
safets type of vaccine
- not a complete virus, cant get an infection
only works if previously uninfected
- best to give before sexual activity 9-13 yrs old but can be up to 26 and if already sexually active + of u have warts (not all are high risk)
for both cervical + testicular cancer
Guardasil + paralysis
Gillian bare syndrome can result in temporary paralysis
but the benefits outweigh the risks, there were more deaths from traffic accidents than those who got GBS
