The Scientific Basis of Vaccines

Question 1

VACCINATION:
What is the definition of a Vaccine?
→ What is required for it to last long?

What are the 2 general principles of Vaccines, in terms of the response it induces?

What are the Durations of Protection that Vaccines can provide?
→ What can be given to increase this Duration?

How long do Maternal Antibodies last in a Newborn?
→ What problems arise with this when wanting to vaccinate the newborn? What protocol has put in to avoid this?

What are the 2 types of Antigens?

Answer 1

• Material from an organism that will actively enhance adaptive immunity - Produces an Immunologically “primed” state, which allows for a rapid secondary immune response on exposure to the antigen
  → Immunological MEMORY
• It should induce the RIGHT TYPE of response and in the RIGHT PLACE
• Short term (Antibody production) vs Long term (Memory cell production)
  → BOOSTERS
• 6 months
  → When giving live, attenuated vaccines, the maternal antibodies will kill the virus, leaving the baby with NO PROTECTION - Can only vaccinate babies after 9 months
• Monotypic (doesn’t change) vs Polytypic (changes rapidly)

Question 2

TYPES OF VACCINES:
1. Live, Attenuated Organism - Give examples of vaccines that use this. How are they produced?
→ Why doesn’t it require any Booster doses?

2. Dead, Whole Organism - Give examples of vaccines that use this
   → What does this require?
3. Subunit Organisms (Individual components) - Give examples of vaccines that use this. What components of the organism are used?
   → What’s the problem with using Polysaccharide antigens?
   → What is done to the Polysaccharide antigens to improve their effectiveness? What does this lead to?

What’s the function of Vaccine Adjuvants?

Answer 2

1. MMR, BCG, VZV, Rotavirus, LAIV - Produced by Serial passage, Low-temperature adaptation, Recombinant genetics, Selection of naturally attenuated strains
   → Live organism is constantly replicating and presenting its antigen to the immune system
2. Pertussis, Polio [Salk type], Hep A, Cholera
   → BOOSTERS
3. Diphtheria, Tetanus, Men C, Hib - Polysaccharide antigens, Proteins, Toxoids, Recombinant proteins, Surface antigens
   → Very poor antigens and Less immunogenic in Children
   → Conjugated with proteins to enhance its ability to produce an immune response in Children = Better Immunity

• Enhance immune response to antigen, Promote antigen uptake and presentation, and Stimulate correct cytokine profiles e.g. Aluminium salts