Principles of Vaccination Flashcards
How are vaccines delivered/administered to animals?
Usually by subcutaneous injection for systemic protection i.e. IgG and T cell production
However, depends on pathogen that is being protected against e.g. intranasal injection for good mucosal protection IgA instead of IgG
e.g. titre, doses
Describe the kinetics of Killed/Subunit Vaccines
Two doses - second dose 4 weeks after the first dose
There is a low titre and short plateau phase after the first dose, after the second dose the titre of antibodies in serum is much higher
Describe the kinetics of MLV/Recombinant virus Vaccines
Requires only one dose - has a high titre of antibodies with a long plateau phase
animal age and doses needed
What is the primary course when vaccinating animals?
The amount of vaccine doses needed varies depending on the type of vaccine, we usually vaccinate after 12 weeks of age as the immune system is immature up to 6 weeks of age and maternal derived antibodies may interfere with vaccination up until around 12-14 weeks of age.
So primary course for vaccination = one dose at 8-weeks and one dose at 12-weeks
Why do we vaccinate at 8-weeks and 12-weeks of age?
Puppies that are early waners (didn’t get a lot of colostrum) don’t have as much protection against pathogens (lose protection by MDA at 8-weeks)
Puppies that are late waners (got lots of colostrum) will have lots of protection and the dose at 8-weeks will not be as effective because of maternal derived antibodies
When do we give booster vaccinations?
First booster usually 1 year after the primary course then following bossters every 1 to 3 years
How do we know if a vaccine has worked?
Serology performed post-vaccination e.g. rabies serology in order to obtain a pet passport
What are the requirements of protective immunity against a virus?
Must produce immune response via neutralising antibody (most vaccines can achieve this)
or
Production of CD8 Killer T Cells (only MLV and recombinant viral vector vaccines can achieve this)
Why must we vaccinate production animals?
Intensive farming increases the risk of endemic infections - the best solution for this is good biosecurity and husbandry practise but vaccination can also be used to reduce the impact of pathogens
Why do some vaccines fail?
Vaccine related problems, human error
- Vaccine does not contain appropriate antigens for the strain/serotype of pathogen to which the host is exposed
- Vaccine has not been stored properly
- Not administered correctly
Why do some vaccines fail?
Host Factors
- Age (such as <6weeks of age or old age)
- Prior exposure to the pathogen
- Animal immunocompromised
- Animal genetically programmed to generate inappropriate response
