(7a) Immunisation

Question 1

Vaccination is the most effective medical intervention, second only to what?

Answer 1

Access to clean water

Question 2

What happened in 1796 in the history of immunisation?

Answer 2

Edward Jenner - inoculation with cowpox virus for protection against smallpox

Question 3

What happened in 1860s-1890s in the history of immunisation?

Answer 3

Louis Pasteur - produced vaccines against chickenpox, cholera, diphtheria, anthrax and rabies

Question 4

What happened in the early 20th century in the history of immunisation?

Answer 4

Toxoid vaccines against diphtheria and tetanus produced following discovery of effective inactivation with chemicals

Question 5

What happened post WW2 in the history of immunisation?

Answer 5

Successful live viral vaccines developed using cell culture technique

Question 6

WHO estimated that how many deaths in 2008 in children under 5 were due to diseases that could’ve been prevented by routine vaccination?

Answer 6

1.5 million

17% of global total mortality in children under 5 years of age

Question 7

6.6 million children under 5 died in 2012. 58% were due to what?

Answer 7

Infectious diseases - globally biggest cause = pneumococcal infection

Question 8

What is the strategic aim of vaccination?

Answer 8

• selective protection of the vulnerable
• elimination (herd immunity)
• eradication

Question 9

What is the programmatic aim of vaccination?

Answer 9

• prevent deaths
• prevent infection
• prevent transmission (secondary cases)
• prevent clinical cases
• prevent cases in a certain age group
• to reduce mortality and morbidity from vaccine preventable infections

Question 10

Why immunise?

Answer 10

• prevent individual disease (life-long, not just children)
• ideally halt carriage and transmission (herd immunity)
• ideally eliminate then eradicate disease
• high coverage is operational target

Question 11

What are the non-specific immune defences?

Answer 11

• unbroken skin
• mucous membranes of gut and lungs
• acid and enzymes of gut
• non-specific metabolism/inactivation

Question 12

What is involved in innate immunity?

Answer 12

• complement
• WBCs
• cytokines

Question 13

What is involved in immune system memory?

Answer 13

• immunoglobin (initially non-specific)
• learns specific IgG response
• lays down immune memory

Question 14

Give an example of passive immunity?

Answer 14

Transfer from mother to unborn baby

Vertical transmission of auto-antibodies from mother to foetus and in breast-feeding

Question 15

What do “maternal antibodies” do?

Answer 15

They can protect the baby for up to a year against illnesses to which the mother is immune

Question 16

Give an example of a maternal antibody

Answer 16

IgG

Question 17

Give an antibody that can be injected into somebody who needs them

Answer 17

IgG

Contains antibodies pooled together from the blood of many donors, can be injected into a person who needs antibodies

Question 18

Is passive immunity effective?

Answer 18

Effective but usually disappears within several weeks or months

Most types of transfused blood contains antibodies

Question 19

What is active immunity?

Answer 19

Long-lasting immunity produced by the immune system in response to antigens

Question 20

Active immunity responds to antigens. Where can these come from?

Answer 20

Can be from natural infection or from vaccinations - the immune system makes antibodies to help destroy these antigens

Question 21

What is the benefit of vaccination in terms of active immunity?

Answer 21

In vaccination, active immunity occurs without disease or disease complications

Question 22

What is “immunological memory”?

Answer 22

The persistence of protection for many years after natural infection or vaccination

B cells persist with the ability to recognise the specific antigen and so can produce IgG antibodies more quickly and in greater numbers

Question 23

What is an antigen?

Answer 23

Anything that can be bound by an antibody

Question 24

Antibodies interact specifically with relatively small parts of molecules. What are these known as?

Answer 24

Antigenic determinants or epitopes

Question 25

What is an epitope?

Answer 25

An epitope, also known as antigenic determinant, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells. For example, the epitope is the specific piece of the antigen that an antibody binds to

Question 26

Antibodies are produced to one specific antigen. Give some examples of different antibodies

Answer 26

IgM IgG IgA IgE

Question 27

The primary immune response develops in the weeks following the first exposure to an antigen. Which antibody does it involve?

Answer 27

Mainly IgM

Question 28

The secondary immune response is faster and more powerful. Which antibody does it involve?

Answer 28

Mainly IgG

Question 29

Which cells are antibodies produced by?

Answer 29

B lymphocytes

Question 30

What triggers clonal expansion of the antibody?

Answer 30

Antigen binds non-specifically to variable region of the antibody molecule - this triggers clinical expansion

Question 31

What happens after antigen binding?

Answer 31

1st wave of IgM production | Followed by IgG production

Question 32

What facilitates the destruction of the antigen-bearing micro-organism?

Answer 32

IgG binds tightly to antigen and through simultaneous complement binding facilitates the destruction of the antigen-bearing micro-organism

Question 33

What happens when infection resolves?

Answer 33

Levels of IgG decline However, one set of the IgG producing B cells persist with the ability to recognise that specific antigen

Question 34

Passive immunity can be vertical transmission from mother to baby or injection of human immunoglobin. Give examples of injection of human immunoglobin

Answer 34

- HNIG - pooled plasma | - specific - tetanus, botulism, hep B, rabies, varicella

Question 35

Give examples of diseases where the live (attenuated) organisms is used in vaccination

Answer 35

- MMR - BCG - yellow fever - varicella They act like the natural infection

Question 36

Give examples of diseases where the inactivated organisms are used in vaccination

Answer 36

- pertussis - typhoid - IPV

Question 37

Give examples of diseases where components of the organisms are used in vaccination

Answer 37

- influenza | - pneumococcal

Question 38

Give examples of diseases where the inactivated toxins are used in vaccination

Answer 38

- diphtheria | - tetanus

Question 39

What are the advantages of using live vaccines?

Answer 39

- single dose often sufficient to induce long-lasting immunity - strong immune response evoked - local and systemic immunity produced

Question 40

What are the disadvantages of using live vaccines?

Answer 40

- potential to revert to virulence - contraindicated in immunosuppressed patients - interference by viruses or vaccines and passive antibody - poor stability - potential for contamination

Question 41

What are the advantages of using inactivated/killed vaccines?

Answer 41

- stable - constituents clearly defined - unable to cause the infection

Question 42

What are the disadvantages of using inactivated/ killed vaccines?

Answer 42

- need several doses - local reactions common - adjuvant needed (keeps vaccine at injection site, activated antigen presenting cells) - shorter lasting immunity

Question 43

What are the types of local reactions that might occur in vaccination?

Answer 43

Local - pain, swelling or redness at injection site, small nodules may form at injection site

Question 44

What are the types of general reactions that might occur in vaccination?

Answer 44

Fever, irritability, malaise, fatigue, headache, nausea, vomiting, diarrhoea, loss of appetite

Question 45

In live vaccines, does the frequency of reactions increase or decrease with increasing number of doses?

Answer 45

Decreases Ab produced in response to live vaccine neutralises the small amount of vaccine virus in subsequent vaccine dose

Question 46

In inactivated vaccines, does the frequency of reactions increase or decrease with increasing number of doses?

Answer 46

Increases If Ab levels are good from earlier vaccination, Ab binds to the vaccine antigen in a subsequent dose leading to an inflammatory response

Question 47

When do vaccine reactions normally occur in inactivated vaccines?

Answer 47

Generally within 48 hours following vaccination

Question 48

When do vaccine reactions normally occur in live vaccines?

Answer 48

Occur according to time taken for virus to replicate

Question 49

When do vaccine reactions occur in the MMR vaccine (live vaccine)?

Answer 49

Reactions to measles component - 1st week following vaccination Reactions to rubella component - 2nd week following vaccination Reactions to mumps component - 3rd week following vaccination (although may occur up to 6 weeks following vaccination)

Question 50

What reaction does the MMR vaccine cause?

Answer 50

Measles component - malaise, fever, rash Rubella component - pain, stiffness or swelling of joints Mumps component - parotid swelling

Question 51

What is the routine NHS vaccination programme?

Answer 51

2 months = DTaP/IPV/Hib + pneumo + rota 3 months = DTaP/IPV/Hib + Men C + rota 4 months = DTaP/IPV/Hib + pneumo 12 months = HiB/Men C + MMR + pneumo 24-48 months = annual flu 40 months = DTaP/IPV + MMR 12 years = HPV for girls 14 years = Td/IPV + Men C 65 years = penumo + annual flu 70 years = shingles

Question 52

At what age is the first dose of MMR given?

Answer 52

12 months

Question 53

Give some recent changes in the UK childhood immunisation schedule

Answer 53

- added more serogroups to pneumococcal vaccination - cease universal adolescent BCG - HPV (and cervical cancer)

Question 54

Give some relatively new vaccines

Answer 54

- varicella/zostavax - menveo - men B - rotavirus - fluenz

Question 55

What is a toxoid?

Answer 55

A toxoid is a bacterial toxin (usually an exotoxin) whose toxicity has been inactivated or suppressed