Vaccinations

Question 1

Recall the immune response to vaccines

Answer 1

1. antigen introduced –> taken by antigen presenting cell
2. presents to naive T-helper cell
3. presents to Naive B-cell –> plasma cells production and antibody production

+ T- cells might enable and kill infectted cells

Question 2

What are the criteria that would make an ideal vaccine?

Answer 2

1. Generates immunological memory
2. Practical - single injection, easy storage, inexpensive
3. No adverse effects

Question 3

What are passive vaccinations? How long does the protection usually last for?

Answer 3

Passive = direct administration of antibodies, not introducing parts that trigger immune reponse

Immunity last for about 3 weeks

Question 4

Name examples of passive vaccinations that can be gien

Answer 4

• HNIG (Human Normal Ig) – Hep A and Measles
• HBIG (Hep B Immunoglobulin) – Hep B
• HRIG (Human Rabies Immunoglobulin) – Rabies
• VZIG (Varicella Zoster Immunoglobulin) – Varicella
• Paviluzimab – monoclonal antibody for RSV (Respiratory Syncytial Virus)

Question 5

What is immune senescence?

What are the drivers of it?

Answer 5

= Natural deteriation of immune system by ageing

1. Increased frequency of terminally differentiated effector memory T cells
2. Increased expression of senescence markers
3. Much reduced production of recent thymic emigrants which drive the naïve T-cell repertoire

Question 6

What is the principle behind a live attenuated vaccine?

Answer 6

Use live pathogen but modified (attenuated) to vaccinate and trigger immune response

Question 7

What are examples of life atenuated avaccines?

Answer 7

MMR
BCG

Yellow fever
Zostavax

Typhoid (oral)
Polio (oral)

Influenza (nasal spary for children 2-17)

Question 8

Shat are the advantage and disadvantages of life attenuated vaccines

Answer 8

Advantages

• Genreally very good immune response
• against multiple antigens (different strains)
• all phases of immune system
  –> may give life-long prottection

Disadvantages

• possible virulence
• potential spread to immunosuppressed contacts

Question 9

What is the rationale behhind inactivated /component vaccines?

Answer 9

Administration of inactivated shell or fragments of membranes that antibodies can be formed towards

Question 10

Name examples of inactivated vaccines

Answer 10

1. Influenza (inactivated)
2. cholera
3. polio (salk)
4. hep A
5. pertussis
6. rabies

Question 11

Name examples of component/ subunit vaccinations

Answer 11

Hep B [HbS antigen],
HPV [Capsid],
Influenza recombinant (less commonly used - inactivated more commonly in adults, life attenuated more commonly in children)

Question 12

What are toxoid vaccines?
Name 2 examples

Answer 12

Diseases where the toxoid are causing disease –> vaccination against effect

Examples
Diphteria and Tetanus

Question 13

What are the advantages and disadvanatages of inactivated or compoundvaccines?

Answer 13

Advantage

• no risk of reversion to virulent form –> immunodeficiency
• easier storge
• lower cost

Disadvantage
* generally poorer immune response –> may need multiple injections or modification to enhance immunogenity

Question 14

What are conjugate vaccines?

Name 2 examples

Answer 14

Sub-type of inactivated vaccines

Something added to enhance T-cell immunity –> better long term protection

Examples of conjugates:
Polysaccarite + proteins e.g.

Haemophilus Influenzae B
Meningococcus
Pneumococcus (Prevenar)

Question 15

What is an adjuvant added to a vaccine?

How do they usually work?

Answer 15

Adjuvant = something that increases the immune response without altering its specificity

MOA - many different MOA, but often mimic action of
1. PAMPs on TLR and other PRR

Prolongs antigen exposure: Alumnninim salts that are only slowly absorbed

Question 16

Explain how mRNA vaccines work

Answer 16

RNA fragment in lipid shells are injected into human
–> RNA integrated and translated to express spike protein on cells

–> stimmulated immune response in T and B cells against expressed protein on cells

Question 17

What are viral vector vaccines? Can you name some examples?

Answer 17

Similar principle to mRNA vaccine, but mode of delivery is viral vector

DNA of relevant protein (Covid spike protein)
inserted to viral vector
to produce vaccine

Question 18

What is the difference between monovalent and multivalent vaccines?

Answer 18

Monovalent = protects against one strain

Multivarlent : protects against several different strains of the pathogen

Question 19

What characteristics should be present in order to make disease eradication possible?

Answer 19

1. No reservoir: animal, latent reservoir in humands
2. onely one or small number of strain
3. vaccine must cause long-lasting immune response

Question 20

What are dendritic cells vaccines?
How are they manufactured?

What is their clinical significance?

Answer 20

Personalised vaccines against certain malignancies –> Dendritic cells are altered to present malignant proteins to trigger immune response against cancer

1. extract dendritic (Antigen-presenting cell, APC) + part of tumour
2. Culture them
3. implant APC back into patient and thy will present t-cells to boost immune response

Question 21

What is the routine UK vaccination scedule for adults?

Answer 21

• 50yrs onwards: flu annually
• 65 yrs: Pneumococcal (PPV)
• 70 yrs: Shingles
• Pregnancy (any age): Flu during appropriate season, DTaP/IPV from 16/40
  gestation

+ COVID