Vaccinology

Question 1

How can we tell that vaccines have been succcessful as a global preventative strategy?

Answer 1

• there has been a reduction in number of cases of diseases

- reducing vaccination would greatly increase the burden of disease within a generation or less

Question 2

Name 5 conditions for which we have vaccines for

Answer 2

• Diphtheria
• H. Influenza
• Hepatitis A
• Hepatitis B
• Measles
• Mumps
• Pertussis
• Polio
• Rubella
• Smallpox
• Tetanus

Question 3

What is a vaccine?

Answer 3

• a preparation that confers acquired immunity to a disease
• without the same risks and side effects as the infection
• make it so that “the first encounter with an infectious pathogen is a secondary exposure”= memory response

Question 4

What you must ensure about a vaccine before it can be disseminated into routine use?

Answer 4

• it is safe to use (non-toxic)
• it doesnt cause the disease its aimed to prevent
• minimal side effects
• its effects are long lasting
• easy to store and transport
• cheap

Question 5

How do active vaccines work?

How do passive vaccines work?

Answer 5

Active: organism causes an immune response to be mounted as if infection had taken place

Passive: provides the vaccinee with a “prefabricated” immune response e..g anti-Hep B antibodies post exposure

Question 6

Describe live vaccines in terms of:

• preparation
• MOA
• contraindication
• advantages

Answer 6

• agents have been weakened but not killed.
• Cannot normally causes disease but can still replicate to produce a strong immune response
• avoid in immunocompromised individuals (risk of actual infection)
• produce strong immune responses, offer lifelong protection, closely mimic natural infection

Question 7

Give an example of live attenuated vaccine

Answer 7

• BCG (TB)
• Shingles
• MMR
• Nasal spray influenza

Question 8

Describe inactivated vaccines in terms of:

• preparation
• MOA
• contraindication
• disadvantages

Answer 8

• agents have been chemically destroyed/ heat
• agent cannot replicate in vivo but immune system can recognise it and mount response
• mount a weaker response so takes several doses (booster) to maintain immune response

Question 9

Give an example of an inactivated vaccine

Answer 9

• Influenza
• Pertussis
• Poliomyelitis
• Typhoid

Question 10

Give an example of a subunit/conjugate vaccine

Answer 10

• Hep B (polysaccharide plus protein)

- TB (experimental stage)

Question 11

Give an example of a toxoid vaccine

Answer 11

• Tetanus

- Diphtheria

Question 12

Novel Hep B vaccinations have been made. What kind of vaccines are they?

Answer 12

• protein/virus like particle

- Subunit vaccine

Question 13

DNA/RNA vaccines are being used against which types of diseases?

Answer 13

• Infections

- Tumours

Question 14

HPV Vaccines are of what category?

Answer 14

• Protein/virus like particle

Question 15

How did Edward Jenner create the first vaccine?

Answer 15

• used pus from a milkmade who had contracted cowpox
• he inoculated a boy with this cow-pox virus containing material
  HE USED AN ACTIVE FORM OF VACCINATION
  (he also injected the boy with actual smallpox virus material which could have been lethal)

Question 16

What is the virus used in vaccine of smallpox?

Answer 16

• Vaccinia virus: laboratory made

- Superior to variola virus (the lethal virus that actually causes smallpox)

Question 17

Human hyper-immune serum is superior to horse serum. Why is it not used?

Answer 17

• Large, serious side effect profile e.g. disseminated intravascular coagulation (DIC), immune haemolysis

Question 18

Outline when childhood diphtheria vaccinations are given

Answer 18

At 8,12, and 16 weeks
- A 6 in 1 vaccine administers as 3 seperate doses

At 3y4month
- 4 in 1 pre-school booster

At 14 years
- 3 in 1 teenage booster

Question 19

Give 4 examples of vaccines given to confer passive immunity

Answer 19

• Hep B hyperimmune serum after exposure
• Tetanus hyperimmune serum after exposure
• Rabies hyperimune serum after exposure
• Anti-venoms, anti toxins given after exposure

Question 20

What has replaced Hep A hyperimmune serum which used to be given after exposure?

Answer 20

Active, pre-exposure vaccine

Question 21

What prophylactic agent is available for babies born to mothers who develop varicella 1 week before or after delivery?

Answer 21

VZV hyperimmune glubulin (VZVIG)

- confer spassive immunity

Question 22

State the known measles vaccine complications

Answer 22

• pneumonia in 6/100
• encephalitis in 1/1000 (also caused by MMR to a lesser extent)
• death in 2/1000
  (apperently damages B cell memory to a number of infections)

Question 23

Outline the concept of herd immunity

Answer 23

• Virus spread stops when probability of infection drops below a given threshold
• The more immune persons the less likely an infected person will transmit to a susceptible person
• This threshold is virus and population specific
• outbreaks of disease can still occur even when threshold is reached

Question 24

What is the herd immunity threshold for measles?

How does this correspond to those vaccinated?

Answer 24

• Threshold is 93-95%

The vaccine is not 100% effective so if 80% are immunized only 76% are actually immune

Question 25

Prior to immunisation how did the Ro (number of secondary transmissions from a single case) compare between the following diseases - Diphtheria, measles, mumps, pertussis, polio, rubella, smallpox

Answer 25

``` Measles (12-18) Pertussis (12-17) Diphtheria (6-7) Rubella (6-7) Polio (5-7) Smallpox (5-7) Mumps (4-7) ```

Question 26

What is the herd immnity threshold for the following diseases -Diphtheria, measles, mumps, pertussis, polio, rubella, smallpox

Answer 26

- Diphtheria: 85% - Measles: 83-94% - Mumps: 75-86% - Pertussis: 92-94% - Polio: 80-86% - Rubella: 83-85% - Smallpox: 80-85%

Question 27

Describe the severe but rare side effect of the swine flu vaccine What was the cause?

Answer 27

Narcolepsy - 1/55,000 - severe sleep disruption, loss of concentration, social difficulties and in severe cases complete loss of muscle control (cataplexy) ASO3 adjuvant

Question 28

What is an adjuvant?

Answer 28

Substances added to a vaccine to increase the bodys immune response to the agent

Question 29

Give an example of micro-fluidized detergent: emulsion, saponin adjuvant Where has it been used?

Answer 29

AS03 - in 2009 swine flu vaccine - in current H5N1 influenza vaccine BLA

Question 30

Give an example of a TLR agonist adjuvant Where has bee used?

Answer 30

CpG (TLR9) | - used in current Hep B vaccine BLA

Question 31

The HPV vaccine contains a combination adjuvant. What is it?

Answer 31

ASO4 - contains MPL which is a TLR4 agonist - and Aluminium hydroxide

Question 32

What is the aim of vaccination?

Answer 32

- Direct aim: provide individual protection | Indirect aim: provide herd immunity

Question 33

What is the serious complication of anti-sera vaccination?

Answer 33

- Can cause anaphylaxis upon repeated administration | response to non self protein- as in anti-diphetheria horse serum

Question 34

In which populations of people might adjuvants be of particular relevance

Answer 34

Those with reduced immunity - elderly - children - transplant recipients

Question 35

What is the relevance of the route of administration of a vaccination?

Answer 35

- many infections are acquired via mucosal surfaces - sensible to induce immune responses at these surfaces - oral administration can result in tolerance

Question 36

Consider meningitis B What is it? Whos most likely to have it? Complications if left untreated

Answer 36

- Medical emergency: an aggressive strain of bacterial meningitis which infects the protective membranes of the brain and spinal cord - Children <5, babies <1 - Septicaemia, severe brain damages

Question 37

Consider meningitis B What are the signs and symptoms in babies?

Answer 37

- fever with cold hands/feet - agitated - continuous crying - sleepy and difficult to wake up - confusion, unresponsiveness - blotchy red rash which doesnt fade when you roll a glass on it