vaccinations

Question 1

when is the BCG vaccination given and for what illness?

Answer 1

neonatal

given to children susceptible to TB

Question 2

when is Hep B given?

Answer 2

first year if born to infected mother

Question 3

what are the main contra-indications for immunisation?

Answer 3

• Anaphylaxis to a previous dose
• Immunosuppression
• Pregnancy
• Postpone if acutely unwell

Question 4

Name bogus contra-indications?

Answer 4

Asthma, antibiotics, breast feeding, neonatal jaundice, prematurity, previous history of infection, allergy

Question 5

what must you do if several live vaccinations are given at the same time?

Answer 5

minimum interval of 3 weeks between them

Question 6

what diseases dont have a vaccine available to them yet?

Answer 6

malaria, worm infestation, TB, respiratory disease, HIV/AIDS, measles

Question 7

what is herd immunity?

Answer 7

• The idea that you should vaccinate a certain percentage of a population that will protect the remaining unvaccinated individuals (around 85%).
• Depends on the pathogen, but generally 90% is required for full HI

Question 8

why may parents not vaccinate their child?

Answer 8

for fear of side effect, judging the risk of vaccine to be higher than the small risk of catching infection

Question 9

when may herd immunity not work to prevent an infection?

Answer 9

Highly contagious infections like chicken pox, whooping cough and measles

Question 10

what are features of an effective vaccine?

Answer 10

safety
protection
longevity
neutralising antibodis
protective t cells
practicality

Question 11

what considerations should be made when designing a vaccine?

Answer 11

• Whole pathogen or recombinant protein?
o Live attenuated or inactivated vaccine
• Does the vaccine require an adjuvant?
o Injected with vaccine to fool body there is an infection
• Which vaccination route? (Mucosal, injection).

Question 12

what are you testing when testing a vaccine and what problems may occur?

Answer 12

Reactions to vaccine administration
o	Anaphylactic reactions
o	Fever / febrile convulsion
o	Local reactions
o	Reversion of live vaccines to ‘wild type’

Problems when pathogen encountered
o Vaccine ineffective
o Heightened immune response to illness

Question 13

what is a vaccination?

Answer 13

improves quality of immune system to fight against a pathogen in the future

Question 14

what is an immunisation?

Answer 14

protecting you from a pathogen but only temporarily

Question 15

what are the types of active immunisation?

Answer 15

• Inactivated – heat-treated

* attenuated – a weaker strain

Question 16

what are examples of passive immunisation?

Answer 16

receiving antibodies, maternal antibodies from mother to baby

Question 17

what are modern vaccines?

Answer 17

recombinant peptide vaccines, DNA vaccine, therapeutic vaccines

Question 18

explain the process of passive immunisation?

Answer 18

• Give injection of killed pathogen
• 10 days later take a blood sample and separate blood cells from serum
• Serum includes neutralizing antibodies
• The serum is then transferred to a different animal
• That animal is then challenged with a live pathogen  animal survives

Question 19

when is passive immunisation given?

Answer 19

given to counteract insect/animal venom

Question 20

what serum is used usually in passive immunity?

Answer 20

horse serum

Question 21

what are the problems with passive immunity?

Answer 21

• The immunisation effect lasts for as long as the antibody remains active – a few months at most
• The patient makes an immune response against the serum (can cause “serum sickness”)

Question 22

what were the 2 types of vaccines or polio?

Answer 22

inactivated vaccine - injected, marinated in formalin, unable to replicate (deactivated)

attenuated vaccine - oral, live weakened polio virus

Question 23

describe the effects of the inactivated polio vaccine

Answer 23

o Vaccine generates good humoral immunity

o No chance of disease (but often side effects)

Question 24

describe the effects of the attenuated polio vaccine?

Answer 24

o Virus can replicate but doesn’t usually cause disease
o The vaccine generates humoral and cell-mediated immunity
o However, occasional polio in vaccinated patients.

Question 25

what is the difference between the inactivated vaccine and attentuated vaccine?

Answer 25

inactivated - needs neutralising antibodies

attenuated vaccines - neutralising antibodies AND cell mediated response

Question 26

what are the side effects of the MMR vaccine?

Answer 26

malaise, fever, rash (at 1wk), febrile convulsions

Question 27

what are the contra-indications of the MMR vaccine?

Answer 27

o Acute illness
o Immunosuppression e.g. steroids, AIDS
o Another live vaccine within previous 3 weeks
o Receipt of immunoglobulin within previous 3 months
o Children who have an anaphylactic reaction to egg should be immunised and observed in hospital for 2 hours

Question 28

what causes diptheria?

Answer 28

Corynebacterium diphtheria

Question 29

what is the incubation period and pathogenesis of diptheria

Answer 29

Incubation period: 2-5 days

Pathogenesis: disease results from exotoxin-producing strains

Question 30

what is the cause of pertussis?

Answer 30

Bordetella pertussis

Question 31

what is the incubation period of pertussis?

Answer 31

7-10 days

Question 32

what are the adverse reactions to pertussis?

Answer 32

• Local: Redness and swelling
• Systemic: Inconsolable screaming, high fever, hypotonic, seizures, anaphylaxis, bronchospasm
• Encephalopathy (very rare, especially with new vaccine – 1.3/10 million)

Question 33

what causes tetanus?

Answer 33

Clostridium tetani

Question 34

what is the incubation period of tetanus?

Answer 34

4-21 days

Question 35

how is tetanus transmitted?

Answer 35

direct transfer of spores

Question 36

what does DPT treat?

Answer 36

Diptheria
Pertussis
Tetanus

Question 37

what are the 2 types of vaccination for hep B?

Answer 37

o Purified from human plasma – HBsAg

o HBsAg produced in yeast cells by recombinant DNA technology

Question 38

how effective is hep b vaccine?

Answer 38

• Vaccine is 90% effective after a 3-dose series (but this decreases over 40 years of age)

Question 39

how long does the hepatitis b vaccine last?

Answer 39

• Duration of protection is at least 3-5 years – booster if concentration Antibody <50 IU/I

Question 40

what is haemophilus influenzae type b?

Answer 40

Encapsulated Gram -ve bacterium – causes bacterial meningitis and epiglottitis in infants and young children

Question 41

describe the method of making recombinant peptide vaccines

Answer 41

• A specific gene is removed from the pathogen
• Gene is added to a culture of yeast
• A single purified viral protein is used for the vaccine
• Mixed with adjuvant to make the vaccine

Question 42

how does recombinant peptide vaccine reduce the risk of side effects?

Answer 42

doesnt use the whole pathogen

Question 43

how do adjuvants work?

Answer 43

• Bias toward Th2 antibody response
• Stimulate mucosal immunity e.g. using pertussis toxin or cholera toxin
• Activate dendritic cells and other APCs
• Bias toward TH1 cell-mediated response (e.g. using IL-12)

Question 44

how are dna vaccines made?

Answer 44

• A specific gene is isolated from the pathogen
• Gene is placed in a bacterial plasmid vector
• Bacterial DNA acts as an adjuvant (via TLR9)
• Plasmid is injected into the muscle of a recipient
• Viral challenge
• Animal is protected

Question 45

how do therapeutic vaccines work?

Answer 45

• An animal is already infected and cannot clear the infection e.g. Herpes simplex 2
• Sick animal is vaccinated to BOOST the immune response to the infection
• Animal can now clear the infection