Vaccination Flashcards
What are the different examples of passive immunity and active immunity?
Passive: Natural maternal Ab, Ig, Antitoxins
Active: Infection, Vaccination
What is colostrum and why is it important for calves?
Claves are born with no resistance to diseases and must acquire this from colostrum, which is in the milk of the mother, they must be fed milk as soon as possible as the Ab given at birth through blood is absorbed rapidly meaning the calf needs mothers milk to sustain energy and immunity
What is an attenuated vaccine?
Live less virulent microorganism yellow fever, measles
What is a live vaccine
Closest to actual infection and therefore elicit good, strong, long lasting immune responses
What are the advantages of live vaccines?
Single dose often sufficient to induce long-lasting immunity
Strong immune response evoked
Local and systemic immunity produced
What are the disadvantage of live vaccines?
Potential to revert to virulence
Contraindicated in immunosuppressed patients
Interference by viruses or vaccines and passive antibody
Poor stability
Potential for contamination
What are inactivated Vaccines?
- Suspension of whole intact killed organism
- Acellular and subunit vaccines
> Contain one or few components of organism important in protection
What are the advantages of inactivated vaccines?
Stable
Constituents clearly defined
Unable to cause the infection
What are the disadvantages of inactivated vaccines?
Need several doses
Local reactions common
Adjuvant needed
Keep vaccine at injection site
Activates antigen presenting cells
Shorter lasting immunity
Describe the process of gaining immunity when a adjuvant vaccine is used?
Dentritic cells present antigen on surface—-> naive T-cell binds to the antigen
T-cell proliferates and differentiates inducing a secoond signal
B-cells activated by the new T-cells
T-cell mediated response
B-cells proliferate and differentiate into plasma cells that produce complementary Ab to the antigen
What does a conjugate vaccine aim to provide immunity against
Some bacteria have a polysaccharide outer coating of that elicit a poor immune responses
Linking the polysaccharide antigen to a protein carrier evokes an effective immune response
can be both T-independant response or T and B-cell collaboration so T-cells are not necessarily needed
When is herd immunity viable?
Virus spread stops when the probability of infection drops the below a critical threshold
What is herd immunity measured by?
Reproduction number which is the average number of new people infected by each infectious case
Basic repro number, R0
R=effective repro number
What happens to the number of cases when the R value is higher or lower than 1?
R>1 cases increases
R< cases decreases
to achieve elimination need to maintain R<1
