Intro to Vaccines

Question 1

Immunisation definition

Answer 1

Process of rendering someone immune or resistant to an infectious disease.

Can be naturally acquired or artificially induced

Question 2

Vaccination definition

Answer 2

Stimulating protective adaptive immunity by exposure to nonpathogenic forms called vaccines

Question 3

Vaccine definition

Answer 3

Live attenuated/killed organisms or microbial components given for prevention of infectious disease.

Can be given as postexposure prophylaxis after exposure to disease causing pathogen

Question 4

Two types of immunisation

Answer 4

Active (Natural infection vs artificial vaccine)

Passive (natural from mother vs artificial antibodies given)

Question 5

Different protection with different types of immunisation

Answer 5

Long term protection for ACTIVE immunity

Short term protection for PASSIVE immunity

Question 6

Current problems active immunisation

Answer 6

Lower uptake of childhood measles vaccine

UK no longer measles free

Question 7

Types of vaccine

Answer 7

Live attenuated virus/bacteria (eg rotavirus, influenza, MMR, BCG)

Inactivated virus (Hep A, rabies)
toxin (diphtheria, tetanus)
subunit (Hep B, meningococcal)

Question 8

Live vs inactive vaccine

Answer 8

Live:
Advantages - single/fewer doses, reproduce natural infection, good protection
Disadvantages - Reversion to virulent wild virus (cause harm), storage issues

Inactive
Advantages - safe, not mutation, stable
Disadvantages - Multiple doses/boosters needed, less effective than live, variable efficacy, high conc required

Question 9

Target population of vaccines

Answer 9

babies (>8 weeks)
Teens (>12-14 years)
Adults (>65)

OR ANY AGE if underlying conditions

Question 10

Routes of vaccines

Answer 10

Oral (rotavirus)
Nasal spray (influenza)
Injectable vaccine (Deltoid area/anterolateral leg of thigh in infant)

Question 11

Mechanism of vaccination

Answer 11

Vaccine antigens and Adjuvant (contain danger signals)
MHC class 2 present antigens to TCR on CD4+
Cd4+ cell activated
PRR recognise Adjuvant
Stimulates T helper cells and CD8+ cell
MHC class 1 presents to CD8+ and activates
CD8+ stimulates effector T cells and memory cells

T helper cell stimulates B cells to proliferate and form memory cells and plasma cell that produce antibody

Question 12

Goals of active immunisation

Answer 12

Long lasting immunity: IgA, IgG, Vaccine specific T cell response, immunological memory
QUICKER and more EFFECTIVE production of IgG
+
Herd immunity

Question 13

What is herd immunity

Answer 13

Indirect protection from infectious disease that happens when a population is immune via vaccination or previous infection.

WHO supports achieving herd immunity via vaccination and not allowing a disease to spread through a population

Question 14

Importance herd immunity

Answer 14

Abolishes circulation of pathogen
Protects immunocompromised
Protects those that respond poorly to vaccines

Question 15

What does herd immunity threshold depend on

Answer 15

The R0 value (reproduction) value of disease

eg. if high R0 value (highly infectious) would need high percentage of immunity to reach herd immunity threshold

Question 16

Immunisations strategies

Answer 16

CHILDHOOD:
Routine immunisation (8 weeks - 14years)
Some non routine if underlying health conditions

ADULT:
Travelling
>65 year olds
Medical conditions

Question 17

Contraindications to giving vaccine (reasons why you shouldnt)

Answer 17

Any severe, local or generalised reaction to previous dose of vaccine (anaphylaxis)

Moderate or severe illness (fever >38.5 degrees)

Question 18

Special considerations when giving vaccine

Answer 18

If mother received immunosuppressants during pregnancy (NO LIVE VACCINES)
Pregnant women (NO LIVE VACCINES)
Allergy to egg, gelatin, neomycin, streptomycin, polymyxin B)

Question 19

When would you not give live vaccine?

Answer 19

Baby whose mother has been on immunosuppressive medication
Pregnant women
Immunocompromised individuals

Question 20

reasons for no live vaccine to immunocompromised individuals

Answer 20

Primary/acquired immunodeficiency (affecting cell immunity)
Within 6 months of chemo/radiotherapy
Bone marrow transplant
High doses of immunosuppressive therapy past 3 months (corticosteroids, methotrexate)

Question 21

Live vaccines UK

Answer 21

Live influenza
MMR
Rotavirus
Shingles
BCG
Varicella 
Yellow fever (travel)
Oral typhoid (travel)

Question 22

Risks vaccines

Answer 22

Common: local reactions, rashes, fever, headache

Very rare: Anaphylaxis

Question 23

False contraindications to getting vaccines (doesnt mean cant get vaccine)

Answer 23

Food intolerance/allergies
Prematurity
Breastfeeding or being breast fed
Currently on antibiotic/corticosteroid therapy
Febrile convulsions/epilepsy 
Underweight
Past age of vaccine schedule
Pregnant women (BUT NO LIVE VACCINE)
Egg allergy and MMR vaccine

Question 24

How to administer vaccine

Answer 24

Intramuscular DELTOID (90 degrees to skin)
Rule out contraindications (cannot have if fever >38.5 or if anaphylaxis to previous vaccine)

If bleeding disorder/blood thinners - hold gauze down after or maybe subcutaneous injection instead

Disinfect area
Gloves

Question 25

Location vaccine

Answer 25

Most muscular section deltoid
3 fingers from acromion
90 degrees and 2cm depth