lecture 5 Flashcards
what is the herd immunity threshold
The number of people with immunity to a pathogen above which a disease will no longer circulate
what are the 4 types of vaccines used today
Attenuated(live viruses)
whole inactivated
capsid and subunit
DNA/RNA
how to live vaccines work
They work by attenuating the virus by inducing mutations which make inate this could be done by growing the culture in high or low temps so that it eveloes getting used to that. then once in a human it nolonger functions properly
This type of vaccine causes the best immune response
what are some cons to live vaccines
They may back mutate causing the stain to become virualent once again causing the disease
cannot used in immon-suppresed indivduals
chance for contamination of un attunated virus
how do inactivated vaccines work
They are replicated in cell culture and then chemically inactived this was once done with formaldehyde but now beta propiolactone is used (virus is dead) this technique involves less risk but is less immno genic
how do capsid and subunit vaccines work
they insert just parts of the virus such as the viral surface proteins which still illsiat a immune repose just not very strong
Recombinant virus vaccines
inserting the genes for immunogenic viral proteins into the genome of another avirulent viurs (carrier)
a majour issue with this type is that you can only use a carrier viruse once
DNA/RNA vaccines
DNA coding for viral proteins under control of a promoter this induces a large immune repose
