Immunisation

Question 1

Goal of vaccination

Answer 1

Strategic aim - Selective protection of the vulnerable, elimination through herd immunity
Programmatic aim - Prevent infection, transmission and death

Question 2

Passive immunity

Answer 2

• Maternal antibodies can protect baby for up to a year

- IG’s from donors are effective at first but disappear

Question 3

Active immunity

Answer 3

• Develop own immunity
• Triggers immune response
• Immunological memory

Question 4

Primary Immune response

Answer 4

• Develops in first few weeks following first exposure to an antigen - IGM

Question 5

Secondary immune response

Answer 5

1. Antibodies are produced by B lymphocytes, antigen binds non-specifically to variable region of antibody molecule, triggering clonal expansion
2. 1st wave of IgM production, followed by IgG production
3. IgG binds to antigen and through simultaneous complement binding facilitates the destruction of the antigen-bearing microorganism
4. When the infection resolves, levels of IgG decline
5. However, one set of IgG producing B lymphocytes persists with ability to recognise that specific antigen = memory B cells

Question 6

Examples of Live organisms

Answer 6

MMR, BCG, Yellow fever, VZV – act like natural infection

Question 7

Inactivated organisms

Answer 7

pertussis, typhoid, IPV

Question 8

What is HNIG

Answer 8

Pooled plasma

Question 9

Advantages of live vaccines

Answer 9

• 1 dose often sufficient to induce long-lasting immunity
• Strong immune response evoked
• Local and systemic immunity produced

Question 10

Disadvantages of Live vaccines

Answer 10

• Potential to revert to virulence and for contamination
• Interference by viruses/vaccines and passive antibody
• Contraindicated in immunosuppressed

Question 11

Advantages of Inactivated/killed vaccines

Answer 11

• Stable
• Constituents clearly defined
• Unable to cause infections

Question 12

Disadvantages of Inactivated/killed vaccines

Answer 12

• Multiple doses
• Adjuvant needed - keep vaccine at injection site, activates antigen presenting cells
• Local reactions are common