Vaccines at the human-animal interface Flashcards
What is the animal human interface in health and disease?
Humans are dependant on animals but this close contact causes diseases. Human health and animal health is interdependant (giving rise to one health).
What is a zoonosis?
A human infection acquired from an animal
Give a breif description of how vaccines were found (poxvirus)?
Smallpox caused by variola virus (DNA poxvirus) was killing lots of people.
Edward Jenner realised that milk maids who’d previously had cow pox did not get this disease.
He infected a child with cow pox and then small pox and immunological memory happened resulting in the kid not dying.
Global eradication of small pox = 1980
What is vaccine scepticism?
People not being sure of vaccines and thinking they are going to be bad for them.
What is morbilliviruses and
Negative strand RNA viruses that can infect humans (measles), cattle (rinder perst), peste des petits rimunants (sheep, goats) and canine distemper (dogs) which are highly contagious via respiratory routes which cause immunosuppresion and mortality.
There is no medical cures but there is however vaccines for these
The measles vaccine?
Live attenuated vaccine
What did measles cause and when was it common?
Common in children
Mild = middle ear infections, diarrhoea, pneumonia
Rare = blindness and encephalitis
What was the MMR vaccine wrongly associated with causing thousands of deaths through people not getting the vaccine?
Autism
Do we have the means to eradicate measles and how would we do this?
Yes - you need to vaccinate enough of the population so that those who cannot be vaccinated will be protected (herd immunity) and better surveillance.
What are the WHO milestones for measles?
Vaccinating more children in their first year of life
Reducing incidence of disease
Reducing mortality
What were the measles deaths like in 2019 and why?
Highest number in 23 years because of parents not vaccinating children.
Has rinderpest been eradicated and how?
Yes because this is only found in animals and therefore they cant massively protest getting the vaccine
What is Kochs postulate?
general guidelines to identify infectious microbes that could be detected with the available methods and that were demonstrably alive
What are benefits of live attenuated vaccines?
Induce strong, protective immunity
What are risks of live attenuated vaccines?
Reaccurance of the disease in non immunised or immunocomprimised people.
What do vaccine platform technologies provide?
Generic approaches to vaccine design and knowledge of immune correlates can accelerate vaccine development
What is involved in the target product profile?
You must thinks about stability, purchase price DIVA, frequency of delivery, duration of immunity, induction of cellular immunity, induction of humoral immunity, route of delivery and multi-valency
what are types of vaccines?
Live attenuated
Killed
Subunit - toxoid, polysaccharide, recombinant antigen with adjuvants
Delivery systems/platform technologies (nanoparticles, vectors, nucleic acids)
How can vaccines induce immunity? (Humoral, antibodies and cell mediated immunitiy)
Humoral immunity (effective against extracellular infections),
Antibodies can neutralise viruses but have limited efficacy against intracellular infections.
Cell-mediated immunity (controls intracellular infections)
How do live vaccines compare to killed/subunit vaccines in the immune response?
Live vaccines elicit a better immune response than killed/subunit vaccines however killed/subunit vaccines tend to be safer but need adjuvants.
What are vaccine platform technologies?
Generic technologies can be applied to vaccines through nanoparticles which have recombinant proteins antigens, vectors encoding antigens of interest, nucleic acid vaccines etc.
These have different properties and offer choice and can accelerate regulatory approval for new vaccines
What was the first human viral-vector vaccines and
ChimeriVax and other viral vectors arent limited to vaccinating against viral disease and epidemics and are now being developed to tackles TB, HIV/AIDs, malaria.
Commonly used vectors include MVA, VSV and Adenoviruses
What are some nucleic acid vaccines?
Human mRNA vaccines
DNA vaccine
Self-amplifying RNA vaccines aren’t approved for use
How does the immune system react to vaccines?
Recombinant adenoviral genome containing promotor, immunogen gene or poly A are injected intramuscularly which causes viral induced activation of the innate signals without any viral particles formed. The immunogen is degraded and expressed on MHC class 1 causing CD8+ T cells to activate
What is the DHSC UK vaccine network?
This is a network which contains all information on possible epidemics and how you would stop them
How were viral vectored vaccines used in the Ebola outbreak?
ERVEBO a live attenuated, recombinant vesicular stomatitis virus besed vector vaccine expressing the enola virus glycoprotien was used.
Why was the covid response so rapid?
Prior knowledge of coronavirus biology, immunology and vaccine platform response
Also lots of countries and many affected individuals.
Altered regulatory processes e.g. they could monitor in real time instead of spending years going through a binder of information
How do the different covid vaccines compare to one another (mRNA, AdV, rProteins)
All used the same S protein
mRNA induced higher antibody levels thans the others. AdV induce better cellular response and CD8+ induction and a Th1 bias associated with better outcomes
How was the safety of covid mRNA vaccines monitored?
VAERS - this involved inputting your data of symptoms into the phone.
They found no correlation between deaths and vaccines
How was rift valley fever an example of one vaccine one health?
Mosquito born virus infecting humans was fatal and caused bu ChAdOx1 encoding RVFV Gn and Gc.
A single IM injection made neutralising antibodies protecting against transmission into humans.
