Vaccinations

Question 1

Define the following terms:
A) vaccination
B) immunization

Answer 1

A) The process of administering a vaccine; exposing a person to material that is antigenic (provoke an immune response) but not pathogenic

B) Process of inducing immunity to disease

Question 2

List 6 reasons why someone shouldn’t be vaccinated

Answer 2

1. Allergy (to something in vaccine) OR reaction to previous vaccine
2. Fever
3. HIV infection
4. Immunodeficiency
5. Neurological disorder
6. Thrombocytopenia; platelet deficiency

Question 3

Name 5 characteristics of a good vaccine

Answer 3

1. Few side effects and low risk of causing disease
2. Low cost (so it can be widely used)
3. Stable with long shelf life (no special storage needs)
4. Long-lasting, appropriate protection
5. The public must see more benefit than risk

Question 4

What is poliomyelitis and how does it affect the body?

What are the three strains and what season is it most common?

Answer 4

An enterovirus (enters through the gut) that enters the body through the mouth (usually from contaminated hands), it travels to the lymph nodes and from here can infiltrate the central nervous system. The motor neurons are particularly affected which can lead to muscle weakness and paralysis (less than 1% of cases, it is mainly an intestinal infection). Problems using chest muscles could lead to death.

3 types: spinal, bulbar and bulbospinal
Most common in the summer

Question 5

Which population was predominantly affected by polio?

What are the virus’s three serotypes and which is the most common and virulent?

Answer 5

Middle class/middle-aged individuals and younger children.

Serotypes: P1 (most common and virulent), P2, P3

Question 6

What kind of vaccine did Salk generate? What was one limitation to this method in general, and why was it not the final solution?

Answer 6

Salk created an inactivated live virus vaccine (e.g; using formaldehyde or other chemical treatment), so the bacteria couldn’t replicate or cause symptoms the left behind epitopes on the virus (acting as the PAMPs presented to the immune system) generated an immune response

One limitation is it doesn’t provoke a strong or long living immune response so you need multiple doses. However, the IPV also only offered immunity for the intestinal tract and did not protect lymph nodes, other tissues and the nervous system from being affected by the virus

Question 7

What was an important feature of Sabin’s attenuated oral polio vaccine, and why did it inevitably not work?

Answer 7

Immediately after the vaccine, people shed weakened viruses in their fecal waste which boosted immunity for others in the community. Inevitably, it didn’t work due to the risk of vaccine-associated paralytic polio

Question 8

Name three advantages and three disadvantages to administering a live vaccine over a killed virus vaccine

Answer 8

Advantage:

1. A live virus can replicate in the host and continually stimulate a protective immune response, so
2. There is no need for multiple doses and
3. The vaccine is longer lasting

Disadvantage:

1. If the virus mutates within the host
2. Side effects (especially individuals with underlying health conditions)
3. Special storage

Question 9

What is a toxoid and what is their purpose? What is one advantage and one disadvantage to using them?

Answer 9

Vaccines with weakened/inactivated components of exotoxins secreted by pathogens. These vaccines are meant to build immunity against the toxins but not necessarily the bacteria producing them.

Advantage: doesn’t cause disease
Disadvantage: Not highly immunogenic and so requires multiple doses

Question 10

How do DNA vaccines work?

Answer 10

A recombinant plasmid containing a gene encoding a specific antigen is created and introduced to humans so it can be expressed by human cells, presented to T cells and provokes an immune response

Question 11

Name a similarity and a difference between subunit vaccines and inactivated whole-cell vaccines

Answer 11

Both don’t contain live components of the pathogen, but subunit vaccines only contain the antigenic parts of the pathogen (single antigen or mixture of antigens)

Question 12

Name the three types of subunit vaccines and briefly describe each type. Name an advantage and a disadvantage to using them generally, and a disadvantage for using each type.

Answer 12

Although they are safer (cannot reproduce) they are often less effective than ‘whole agent’ vaccines and require boosters (and are costly)

1. Protein-based: A specific protein of the pathogen is isolated and used. However, if the protein is denatured the immune response will be inadequate
2. Polysaccharide: polysaccharide from the bacterial cell wall is used in the vaccine. But this vaccine only stimulates B cells?
3. Conjugate: based on the polysaccharide vaccine plus another carrier protein that has a better immunogenic response/helps expose it better to the immune system. This generates a T cell response and gives longer coverage, although a booster might still be needed. The conjugate effect also has the potential to causes secondary effects

Question 13

Name two things that can be done to overcome subunit vaccine problems

Answer 13

1. Multiple doses/booster shots
2. Adjuvants: prolong stimulation of immune system by trapping the antigens in a chemical complex and releasing them slowly

Question 14

Name two examples of adjuvants that can be used alongside subunit vaccines

Answer 14

1. Aluminum salts

2. Monophosphoryl lipid A

Question 15

Name 5 routes of administration for a vaccine, which is the most common?

Answer 15

1. Deep cutaneous or intramuscular - most common
2. Oral
3. Intradermal
4. Scarification
5. Intranasal

Question 16

What is a depot injection?

Answer 16

An implant that sits in the subcutaneous tissue

Question 17

List the three ‘premixed’ forms of vaccines

Answer 17

1. Single-dose ampule; a premeasured, single dose
2. Multi-dose; i.e insulin
3. Pre-filled syringe

Question 18

When do you use a blunt fill and a blunt filter needle and why?

Answer 18

Both reduce the risk of sharp injuries:
Blunt fill; used when drawing up from vials
Blunt filter; used when drawing up from ampoules and the filter prevents the uptake of any micro-glass particles

Question 19

What angle would you give an IM and subcutaneous needle?

Answer 19

90 degrees (45 degrees if there is less subcutaneous tissue i.e; children and underweight adults)

Question 20

List two reasons to choose a subcutaneous injection, and name two medications that are commonly given by this route

Answer 20

When to choose this route:
1. Medication requiring slow systemic absorption
2. Administering small amounts of medication (~1ml)
+ Meds have to be fat-soluble

Insulin, heparin

Question 21

List two reasons to choose an IM injection

Answer 21

When to choose this route:

1. If meds would irritate tissue if given less deeply
2. If larger amounts of meds are necessary

Question 22

What is an important technique to remember when giving an IM injection vs a subcutaneous one?

Answer 22

Must drawback on the needle during an IM injection to ensure no blood comes up as you don’t want to inject straight into the bloodstream

Question 23

List the four most common areas for IM administration, how the patient should be positioned for each and their respective limitations and advantages

Answer 23

1. Dorsogluteal (back of hip); beware the sciatic nerve, not for children under 3 as their muscles in this area haven’t sufficiently developed, the injection can be up to 3 ml, the patient should be lying down so muscles are less tense
2. Ventrogluteal (side of hip); the patient should be in a side-lying position, safer and less painful than dorsogluteal, the injection can be up to 3 mL
3. Deltoid; only small amounts of meds (1-2 ml), not used for infants and toddlers
4. Vastus lateralis (side of thigh); can be used for infants and children younger than 3, little risk of injury (no large nerves or arteries around here)

Question 24

Name two meds commonly given in the deltoid muscle

Answer 24

1. Hep B vaccine

2. Tetanus toxoid

Question 25

Name two ways immunity can be acquired and the natural and artificial components of each

Answer 25

1. Actively; through your own antibodies A) natural exposure B) Immunization (artificial) 2. Passively; ready-made antibodies... A) Maternal antibodies (natural) B) Antibodies from other sources (artificial)

Question 26

When does our passive immunity peak?

Answer 26

Just prior to birth

Question 27

Define attenuation and describe the process

Answer 27

A process that lessens the virulence of a microbe 1. A pathogenic virus is isolated from the patient and grown in human cells 2. Infect monkey cells (with the cultured virus) 3. Over time, virus acquires mutations allowing it to grow well in monkey cells but UNABLE to grow well in human cells (less virulent) This culture is now a vaccine candidate as the immune system will recognize its PAMPs and DAMPs but the pathogen is unable to cause harm

Question 28

Name one advantage and three disadvantages of using an attenuated vaccine. List two viral and bacterial examples

Answer 28

Advantage: weakened live organism should produce a full and long-lasting response after 1-2 doses Disadvantages: 1. mild form of the disease may occur 2. Immunocompromised patients may not be able to overcome the weakened version 3. Rarely the attenuated virus may mutate to its virulent form before the immune system develops a response

Question 29

Name an example of a conjugate vaccine

Answer 29

Haemophilis influenza type B vaccine

Question 30

How do carrier vaccines work?

Answer 30

Introducing a single gene from a pathogenic microbe into a virus that doesn't cause disease creates a 'Trojan horse carrier vaccine'. When the carrier infects the APCs, the cells produce the pathogenic microbe proteins as well as the carrier proteins. This generates memory killer T cells without the vaccine being able to cause disease, as only 1 or 2 of the pathogen's genes are carried by the vaccine.

Question 31

Name the three major things a vaccine is composed of

Answer 31

1. Active immunizing agent 2. Preservatives, stabilizers, antibiotics 3. Adjuvants

Question 32

What are adjuvants and why are they used? | Name one previously widely used example

Answer 32

Substances that are given together with a vaccine to heighten the vaccine's effectiveness. They are from microorganisms and are added to proteins to trigger a 'danger signal' to the immune system. They prolong the period of time the vaccine can stimulate an immune response and/or attract phagocytic cells E.g; aluminum hydroxide

Question 33

Define Population (herd) immunity and list four factors it depends on

Answer 33

Population immunity is the state achieved when immunization programs reach a high enough coverage of the target population to prevent transmission within the community. Depends on; how infectious the disease is, the efficacy of vaccines, environmental factors, the vulnerability of the population

Question 34

Why is herd immunity so important?

Answer 34

Protects those who cannot be vaccinated i.e; those.. 1. immunodeficiency (including those without a working spleen, chemo, HIV) 2. Newborns who are too young to be vaccinated 3. Elderly 4. Pregnant 5. Those who are ill in hospital

Question 35

Define an adverse vaccine reaction

Answer 35

A systemic or local response to a drug that occurs at doses normally used which is noxious (harmful) and unintended

Question 36

How does polio resist extreme environments?

Answer 36

Its heat resistant, tolerates an acidic environment with a pH of 3-5 for up yo 3 hours and is resistant to many detergents and disinfectants