Vaccination to Prevent Infection

Question 1

what does the term vaccine derive from?

Answer 1

vaccinia virus

Question 2

describe innate immunity

Answer 2

• first line of defence
• physical barriers and fluids
• non-specific rapid cellular responses
• relies on cells that can digest pathogens and can present

Question 3

what cells are present in innate immunity? (6)

Answer 3

phagocytes
- neutrophils, basophils, eosinophils

natural killer cells
dendritic cells
macrophage

Question 4

describe adaptive immunity

Answer 4

• antigen specific, tailored defence
• days to develop
• long-lasting memory
• B cells, T cells, antibodies

Question 5

define passive immunity

Answer 5

conferring immunity by using antibodies derived from another host

e.g. through breastmilk

Question 6

define active immunity

Answer 6

using modified/killed pathogens or their antigens to stimulate an immune response

e.g. vaccination

Question 7

describe the immunological concept behind passive immunisation

Answer 7

• short lived
• no memory funciton
• often modify infection rather than prevent

Question 8

what agent is available for active immunisation?

Answer 8

Vaccines

Question 9

3 aims of vaccines.

Answer 9

1. present viral protiens (antigens) on antigen presenting cell
2. trigger adaptive immune response
3. create immunological response

Question 10

list 5 types of vaccines

Answer 10

live attenuated
inactivated
mRNA
non replicating viral vector
subunit

Question 11

what are live attenuated vaccines? give 2 pros and 4 cons.

Answer 11

• weak live virus particles

pros
- mimics natural infection
- effective and immunogenic

cons
- can get systemic side effects
- unsuitable for preggers or immunosuppressed
- requires cold chain
- possibility of reversion to wild type virus

Question 12

name 4 live attenuated vaccines.

Answer 12

measles
yellow fever
intranasal influenza
oral polio vaccine

Question 13

what are adjuvants? give 3 examples and 1 downside.

Answer 13

ingredients used in inactivated vaccines to provoke a stronger immune response

aluminium salts
oil in water emulsion
addition of other chemicals

• may cause local or systemic reactions

Question 14

describe inactivated vaccines. give 3 pros and 3 cons.

Answer 14

the whole virus is inactivated or killed by chemical/heat
- not infectious but still has immunogenicity

pros
- suits most people
- no risk of reversion to wild type
- fewer systemic side effects

cons
- multiple doses required
- require adjuvants or conjugates
- can cause local reactions

Question 15

give 4 examples of inactivated vaccines.

Answer 15

hepatitis A
rabies
inactivated influenza
inactivated polio

Question 16

what types of agents are available for passive immunisation? give examples

Answer 16

human normal immunoglobulin
- exists in the blood of individuals
- gather from pooling multiple blood donations
- product can confer immunity through transfusion

hyperimmune globulin

monoclonal antibodies

Question 17

what is post exposure prophylaxis?

Answer 17

giving medication to prevent or control the spread of infection

Question 18

describe human normal immunoglobulins as passive immunity. give 3 indications

Answer 18

pooling multiple blood donations
1,000-15,000

indications
- post-exposure prophylaxis for measles or hepatitis A
- those unlikely to mount immune response
- those unable to make a live vaccine - immunocompromised

Question 19

describe hyperimmune globulins as passive immunity. give an indications and examples of diseases.

Answer 19

pooling screened blood donations with known antibodies

indications
- post-exposure prophylaxis for
- rabies
- varicella zoster
- hepatitis B

Question 20

define monoclonal antibodies for passive immunity and an important feature they have

Answer 20

genetically engineered antibodies produced form a white blood cell clone

have monovalent affinity
- binds to specific epitope of an antigen
- can target parts of a virus

Question 21

give 2 examples of monoclonal antibodies.

Answer 21

Palivizumab
- given to babies
- for respiratory syncytical virus

Sotrovimab
- COVID-19

Question 22

what are subunit vaccines? give 2 pros and 3 cons

Answer 22

antigen subunits of the virus, not the complete virus - no genetic material

pros
- safer - no genetic material, no replication
- focuses the immune response on the important bits of the virus

cons
- require multiple doses
- require adjuvants
- may have local and systemic reactions

Question 23

give 4 examples of subunit vaccines.

Answer 23

hepatitis b
HPV
diphtheria
tetanus

Question 24

describe non-replicating viral vector vaccines. 2 pros and 2 cons.

Answer 24

a low pathogenic virus is engineered to contain the genetic material of the disease-causing virus

SO a low pathogenic virus produced disease-causing viral protiens

pros
- safe and effective
- good immune response

cons
- higher dosage needed
- may not work if person is immune to the low pathogenic virus

Question 25

give examples of non-replicating viral vector vaccines.

Answer 25

covid-19
ebola

Question 26

describe mRNA vaccines.

Answer 26

• self-replicating mRNA
• translated by host cells
• produce viral antigens

Question 27

what does the vaccine need to do, to be able to eradicate disease?

Answer 27

• prevent infection
• activate immune response
• herd immunity