Vaccines 131021

Question 1

how does the immune response to vaccine work

Answer 1

o APC macrophage/DC take up antigen via PRR (detect PAMPs and DAMPs)
 PRR = Pattern Recognition Receptor
 PAMP = Pathogen Associated Molecular Pattern
 DAMP = Damage Associated Molecular Pattern
o APC present antigen to naïve helper T-cell  activated T-cell  activates associated B-cell  plasma cells
o Plasma cells produce specific antibodies
o Antibodies lead to:
 Neutralisation of infectivity
 Antibody-dependent cellular cytotoxicity
o If an attenuated virus vaccine is used, the T cell response is very important in destroying infected cells
o At the end of these processes, the main goal is to produce memory cells to the vaccine antigen
 Memory B cells
 Memory killer T cells
 Memory T helper cells

Question 2

examples of inactivated vaccines

Answer 2

influenza, polio, cholera

Question 3

what are the advantages of inactivated vaccines

Answer 3

stable constituents clearly defined, unable to cause infection

Question 4

Disadvantages of inactivated vaccines

Answer 4

needs many doses local reactions common, adjuvant needed

Question 5

examples of live attenuated vaccines

Answer 5

MMR YELLOW FEVER

Question 6

What is the risks with live attenuated vaccines

Answer 6

Modified to be less virulent but avoided in pregnant and immuno compromised as risk of virulence

Question 7

toxoid vaccines

Answer 7

diptheria tetanus

Question 8

Subunit vaccines

Answer 8

HBV HPV protein components of microorganism lacking viral genetic material

Question 9

Conjugate

Answer 9

nhs bacteria, poorly immunogenic antigens are paired with a protein that is highly immunogenic

Question 10

heterotypic

Answer 10

e.g. BCG using pathogens that infect other animals but not humans

Question 11

what are the components of a vaccine

Answer 11

• Stabilisers are substances added to keep it chemically stable for transport from the site of production to the site of use
• Aluminium hydroxide is a commonly used adjuvant
• Preservatives are particularly important for multi-use vaccines where you don’t want the vials to be contaminated
• Antibiotics are used to prevent contamination
• Some trace components are left from the vaccine manufacture process

Question 12

Vaccination programmes considerations

Answer 12

• Vaccination should be administered before the peak-age-incidence of the disease
• Vaccination programmes either targeted towards high risk groups or widely disseminated to everyone
• Effective R0 needs to be <1
• Catch up campaigns to pick up anyone that missed vaccinations should be considered

Question 13

prerequisites for successful disease eradication

Answer 13

• No animal reservoir
• Antigenically stable pathogen with only one/few strains
• No latent reservoir of infection and no integration of pathogen genetic material into the host genome
• Vaccine must induce a lasting immune response
• High coverage required for very contagious pathogens (e.g. measles)

Question 14

uk measles and rubella elimination strategy

Answer 14

o (1) Achieve and sustain ≥95% coverage with 2 doses of MMR in the routine childhood programme (<5 years old)
o (2) Achieve ≥95% coverage with 2 doses of MMR vaccine in older age cohorts through opportunistic and targeted catch-up (>5 years old)
o (3) Strengthen measles and rubella surveillance through rigorous case investigation and testing ≥80% of all suspected cases with an Oral Fluid Test (OFT)
o (4) Ensure easy access to high-quality, evidence-based information for health professionals and the public