Scientific Basis of Vaccines Flashcards
What are the 4 principles from Jennerβs experiments?
1) challenge dose - proves protection from infection
2) Concept of attenuation
3) Concept that prior exposure to agents boosts protective response
4) cross species protection - antigenic similarity
What were the three things that contributed to smallpox eradication?
β They had vaccination programmes
β Case finding (surveillance)
β movement control
What were the 5 things that made the eradication of smallpox possible?
1) No subclinical infecitons (no asymptomatic spreaders)
2) after recovery the virus was eliminated - no carrier states
3) No animal reservoir
4) effective vaccines
5) slow spread and poor transmission
What is the definition of a vaccine?
β material from an organism that will :
β actively enhance adaptive immunity
β produces an immunologically primed state that allows for rapid secondary immune response on exposure to the antigen
β prevent disease but not infection
What are the 4 complications in measles?
β 1 in 15 pneumonia
β otitis media
β bronchitis
β 1 in 5000 encephalitis
What are the 2 complications of the measles vaccine?
β 1 in 1000 fever/convulsions
β 1 in 400,000 meningo-encephalitis
What is one complication of diphtheria?
β 5% mortality
What is one complication of the diphtheria vaccine?
β occasional swelling
What are the 2 complications of whooping cough?
β 0.1% mortality
β frequent pneumonia, encephalopathy
What is one complication of the whooping cough vaccine?
β 1 in 600,000 encephalopathy
How can active immunity be induced?
β Natural exposure
β Infection
β Vaccination
What is the duration of active immunity?
β long term
How does passive immunity occur?
β prophylaxis / treatment
What is the duration of passive immunity?
β short term
Give three examples of passive immunity?
β anti-tetanus serum from horses in WW1 decreased mortality by 30x
β post-exposure protection in rabies + vaccine
βpooled human immune serum with high amounts of antibodies to protect babies from VZV
How long does it take for an antibody response during primary exposure?
β 5-7 days
How long does it take for a full response during primary exposure?
β 2 weeks
What class switching occurs in antibodies during a primary exposure?
β IgM β IgG
How long does a full response take during secondary exposure?
β 2 days
What components are used to make a vaccine from a bacteria or a virus and why?
β usually surface proteins
β if you use a protein from inside the bacteria or virus, the body never comes into contact with the protein because it is internal
What are good targets for vaccines?
β Surface proteins
β polysaccharides
β toxins
What are 4 important considerations when vaccinating?
1) inducing the correct type of response
2) Inducing the response in the right place
3) duration of protection
4) age of vaccination
What kinds of responses are induced with polio and TB?
β Polio : antibodies
β TB : cell mediated immunity
Where should the immune response be with flu, polio and yellow fever?
β flu, polio : mucosal
β yellow fever : systemic
Why do you need a mucosal response with the flu and polio?
β Flu affects the respiratory system
β polio affects the gut
Which one of paraenteral and oral vaccines provide the best mucosal immunity?
β oral vaccines because they are processed by MALT (mucosal associated lymphoid tissue) and have good IgA
