Immunisation

Question 1

When did principles of immunisation first established?

Answer 1

Date back to the ‘nineteenth century’

When Edward Jenner published the 1st description of vaccination against small pox

Question 2

Negative example in the history of immunisation/vaccination

Answer 2

In 1906,

A cholera vaccine study accidentally muddled “vaccine serum” with “bubonic plague serum” >>> infected and killed 13 participants

(But we should NOT dwell on that, immunisation has immeasurable benefits to society & to eradication of many diseases)

Question 3

Positive example in the history of immunisation/vaccination

Answer 3

Near eradication of polio in the world

More than 60 thousands in 1980 to in few hundreds cases in 2004 in the whole world

Question 4

How can immunisation against a specific pathogen be generated artificially?

Answer 4

Either actively or passively

Question 5

Principles of passive immunisation

Answer 5

Administration of pre-formed antibodies against a particular antigen

Question 6

Passive immunisation: Examples

(Preformed antibodies: Examples)

Answer 6

• Tetanus
• Varicella
• Rabies
• Hepatitis B
• Botulism
• Diphtheria

Question 7

Passive immunisation: advantage

Answer 7

It provides instantaneous immunity within 24 to 48hours

Question 8

Passive immunisation: Time of use

Answer 8

Immediate post-exposure prophylaxis

Question 9

Why is passive immunisation (pre-formed antibody) given as immediate ‘post-exposure prophylaxis’?

Answer 9

Because it provides instantaneous immunity within 24 to 48hours

Question 10

Passive immunisation: disadvantges

Answer 10

• Immunity only lasts for the half-life of the immunoglobulin (30days)
• As it is a blood derived product >>> risk of TTIs (Transfusion transmitted infections)

Question 11

Principles of active immunisation

Answer 11

To expose the ‘adaptive immune system’ to a stimulus (virus, bacteria, toxin) >>> to generate a lasting response

Question 12

Different methods of active immunisation/vaccination

(Different types of vaccines)

Answer 12

• Live vaccines
• Killed vaccines
• Subunit vaccines

​Killed and subunit vaccines are more common than live vaccines

Question 13

Live vaccine: Examples

Answer 13

• Yellow fever
• MMR (Measles-Mumps-Rubella)
• BCG (Bacille Calmette Guerin)
• Varicella (Also has pre-formed antibodies)
• Oral Polio (No longer available in the UK)

Question 14

Killed vaccines (=Killed whole organism): Examples

Answer 14

• Seasonal flu (Annual flu jab)
• Typhoid
• Rabies (Also has pre-formed antibodies)
• Pertusis
• Cholera
• Parenteral polio

Question 15

Subunit vaccines (= Subunits of organism): Examples

Answer 15

• Pneumococcus (Pneumococcus polysaccaride vaccine: PPV or PPSV)
• Hib (Haemophilus influenzae type B)
• Hepatitis B
• Meningococcus
• HPV (Human papilloma virus)

Question 16

Why do we use live vaccines (containing live organisms)?

Answer 16

Some antigens are inherently less immunogenic

Question 17

Live vaccine: contraindications

Answer 17

Immunodeficiency (primary or secondary)

Question 18

Conjugate vaccine: Examples

Answer 18

Prevener: Conjugate pneumococcal vaccine

(Conjugated polysaccaride vaccine with a protein)

Question 19

Polysaccaride vaccine is conjugated with what?

Answer 19

A protein

Question 20

Conjugate vaccine: advantages

Answer 20

Conjugation stimulates a cellular response >>> improves likelihood of protective immunity

Question 21

Are vaccination/immunisations 100% protective/effective?

Answer 21

NO

No vaccine is 100% effective

Question 22

If immunisations are NOT 100% effective, upon which do they rely on?

Answer 22

On the principles of “herd immunity”

Question 23

Concept of herd immunity

Answer 23

It relies on the premise that >>>

• For infections to gain ground in a population >>> they need to spread in chain from one person to the next
• If a significant proportion of the population has reduced susceptibility >>>>> these chain fails to develop >>>>> infection rates diminish in both vaccinated and unvaccinated individuals