Vaccines

Question 1

How does a vaccine work?

Answer 1

*antigens, on the surface of the weakened or dead bacteria or viruses introduced into blood
*antigen presenting cells (APC’s) capture and ingest antigen and express on their surface
*APC’s move to cluster of immune cells. Activate T cells, trigger killer T cel,s and maturation of B Cells
*naive killer T cells become mature killer T cells specific to the antigen,
*if vaccine live- t killer cells destroy cells
*now have memory killer T cells
*b cells produce antibodies binding to antigens, marking for killer T cells
*memory b cells produced

Question 2

What are characteristics of an ideal vaccine?

Answer 2

*produce immune protection without causing disease
*generate long lasting immunity
*interrupt infection spread

Question 3

What types of vaccines are there ?

Answer 3

*live weakened
*inactivated
*subunit- conjugate
*nucleic acid vaccines- RNA

Question 4

What are advantages of live weakened vaccines?

Answer 4

*most potent vaccine - mimic real infection
*strong immune response
*long term immunity after one or two doses

Question 5

What are disadvantages of live weakened vaccines?

Answer 5

*potential to revert to infectious form
*poor stability- strict storage and transport conditions
*not given to immunocomp

Question 6

What are examples of live weakened vaccines?

Answer 6

*shingles
*measels

Question 7

What are examples of inactive vaccines?

Answer 7

*polio
*influenza

Question 8

What are advantages of inactivated vaccines?

Answer 8

*safer than live weakened
*more stable- easier to store

Question 9

What are disadvantages of inactivated vaccines?

Answer 9

*if not treated well enough, can leave live infectious agents in vaccine
*requires booster

Question 10

What are advantages of subunit vaccines?

Answer 10

*only part of antigen used- not whole pathogen so saved
*can be given to immunocomp

Question 11

What are disadvantages of subunit vaccines?

Answer 11

*complicated to manufacture
*local side effects more common ie pain at injection site

Question 12

What is an example of a conjugate subunit vaccine?

Answer 12

Pneumococcal vax

Question 13

What are nucleic acid vaccines?

Answer 13

*do not supply antigen
*supply rna of antigen to develop immunity

Question 14

What are advantages of nucleic acid vaccines?

Answer 14

*safer- don’t contain whole pathogen
*easy to make

Question 15

What are disadvantages of nucleic acid vaccines?

Answer 15

*ultra low storage <70°C
*boosters

Question 16

How does the Covid 19 RNA vaccine work?

Answer 16

*mRNA injected
*mRNA of spike protein of SARS-CoV-2 (antigen)
*mRNA taken up by host cell, which translates genetic info into producing spike proteins
*stimulates immune system to produce antibodies and activate T cells

Question 17

What is a viral vectored vaccine?

Answer 17

*vector carries genetic sequence for antigen (or spike protein)
*stimulates immune system, make antibodies, activate T cells
(AstraZeneca vax)

Question 18

How does the viral vector vaccine by AstraZeneca work for Covid?

Answer 18

*non replicating viral vector vaccine
*used part of weakened adenovirus as Carrier to deliver genetic sequence for SARS-CoV-2 virus spike proteins
*modified adenovirus binds to host cells, delivers mRNA for spike protein
*stimulates immune system

Question 19

What ingredients in a vaccine provide immunity?

Answer 19

*antigen- active component or RNA of it- generate immune response
*adjuvant- improves immune response to vaccine- aluminium phosphate

Question 20

What ingredients in a vaccine keep them safe and long lasting?

Answer 20

*preservatives- prevent contamination once open- 2-phenoxyethanol
*stabilisers- prevent chemical reactions occurring within vaccine- keep vax components sticking to vial- sugars
*surfactants- keep all ingredients blended together- prevent settling and clumping- polysorbate 80

Question 21

What two extra ingredients are in vaccines?

Answer 21

*residuals- tiny amount of substance used during manufacture- yeast, antibiotics
*diluent- dilute to correct conc- sterile water

Question 22

Apart from the API in a vaccine, what is the other main ingredient?

Answer 22

Water

Question 23

What phases are there in vaccine clinical trials?

Answer 23

*preclinical- animal testing- if triggers immune response, tested in humans
*phase 1- small no of HEALTHY individuals-assess safety and dose
*phase 2- several hundred- volunteers with same characteristics ie age and sex- asses safety, dose and confirms immune response
*phase 3-thousands of volunteers- determines efficacy, assess safety in large group
*phase 4- ongoing studies

Question 24

At what temperatures are vaccines stored?

Answer 24

*2-8°C
*-20°C
*-70°C
Term- cold chain

Question 25

What is the purpose of cold chain in vaccines?

Answer 25

*maintain vaccine product integrity from time of manufacture to administration
*storage outside recommended leads to: formulation degradation, product contamination, loss of potency, substandard immune response

Question 26

What muscle are vaccines administered into usually?

Answer 26

Deltoid (upper arm)
*if unsuitable, vastus lateralis (middle thigh)

Question 27

How is a vaccine administered IM?

Answer 27

*identify correct site
*stretch skin at site
*insert at 90° angle
*depress plunger
*gently remove needle
*apply light pressure if bleeds

Question 28

What are the benefits of administering vaccine into muscles?

Answer 28

*better immune response- muscle contains cells to initiate immune response
*less likely to cause local reaction

Question 29

What are challenges in vaccinations?

Answer 29

*anti vax movement
*social media
Myth: contain mercury which is dangerous- very few contain thiomersal- no evidence risk to health