Vaccination L15 Flashcards
what is passive immunisation
administering preformed antibodies eg derived from blood donors, animals
what is the problem with injecting antibodies
inject antibodies and immediately work
Problem that the antibodies have a finite half-life, they are then again just as susceptible
what is protection for passive immunisation
immediate
what memory is caused by passive immunisation
No immunological memory generated
what response is caused by passive immunisation
No immune response stimulated in the recipient
what is active immunisation
Stimulate host to generate immune response
what is a vaccine
collection of immunological determinants which stimulate host immune system leading to generation of an appropriate immune response
what do Th B cells make
antibody
what is the Th B cells response
humoral response
what do Th Tc cells make
cell mediated immunity
what is the primary immune response graph like
Primary doesn’t go that high and goes
back down
what is the secondary immune response graph like
Shorter time to be generated as some memory b cells left from first immunisation, will last longer possibly life
what is the primary immune response like
Long lag period
Lower level of response
Shorter-lasting
what is the secondary immune response like
Faster
Higher level of response
Longer lasting
what is the aim of vaccination
Create immunological memory
Generate secondary rather than primary response when challenged
- increase speed
- increase magnitude
what should a vaccination do
Tip balance of virus/host interaction towards HOST
what are the types of vaccine
live/dead
live attenuated
dead
what must happen to live vaccines to be used
attenuated
what is attenuation
Manipulate the genome of the virus to make it not pathogenic
Molecular manipulation
how is an attenuated vaccine made
through trial and error
As disease grows in cell culture it will adapt and change due to mutations, this will cause it to be attenuate
what do live vaccines cause
broad response - all parts of organism
humoral and cellular
what happens when live attenuated vaccine injected
replicate once injected, cause an amplification of the response, all the proteins of the virus are expressed = broad response
how many doses of live attenuated vaccine needed
may require only single dose
what are the disadvantages of live vaccines
Reversion to virulence - e.g. polio excreted in bowel Not applicable to all organisms Storage problems - Cold-chain
examples of live vaccines
Polio (Sabin) – no longer used in UK
Measles, Mumps, Rubella
BCG
what are dead vaccines
Short-lived immunity
Multiple doses + boosters
Must be sure its dead!
Killing may alter structure
advantages of dead vaccines
No reversion to virulence
More stable
how are the dead vaccines subunit made
Prepared by molecular biological techniques
example of dead vaccines subunit
Hepatitis B virus – vaccine is HBsAg only
what is a dead vaccine
Purified, is not live, cannot get disease as it never contained whole virus, only the surface antigen to get immunity against it
what happens with dead vaccine subunit: Hepatitis B virus – vaccine is HBsAg only
Surface antigen that binds to liver cells in hepatitis B – need decent antibodies against the surface antigen to prevent hepatitis B
how can vaccines be administered
intramuscular
subcut
oral
inhalation
what makes a vaccine work better when administered
Need the immunity at the site of infection, if can administer the vaccine like how infects will work better
is more doses better
more doses less likely to be effective
what are the contradictions to vaccination
- Acute febrile illness - if patient is ill should postpone vaccine
- Allergy to vaccine component
- Immunodeficiency
- Pregnancy, not vaccinated unless necessary
- Many false contraindications
what is false contradiction
many false reasons people give for not wanting to be vaccinated
what must be considered with vaccinations
risk of infection
will the vaccine work
what are the risks of vaccination
cost of vaccination
what are the risks of vaccinations
- adverse reactions
- vaccine stability - storage, reversion to virulence
- particular risks - pregnancy, immune deficiency, allergies, other therapy
