Module 3

Question 1

Immunization

Answer 1

Process by which resistance to an infection is induced (think “vaccination”) or augmented (think “booster shots”). Immunization allows us to develop immunity without having the disease.

Question 2

Immunity

Answer 2

Resistance to a specific disease

Question 3

Antigen

Answer 3

“Substance” that induces the immune response ex. Bacteria, viruses

Question 4

Antibody

Answer 4

“Products” of immune response; globulin type of protein

Question 5

Antibodies

Immunoglobulin

Answer 5

IgM:

• first antibody produced in an immune response
• indicates current or recent infection or exposure to antigen

IgG:

• second antibody produced in the immune response
• indicates past infection (when IgM absent)

Question 6

Antibody production

Answer 6

1. Antigenic stimulation of B cells yields:
   - clone of antibody-producing cells (plasma cells)
   - clone of memory cells (ready to jump into action if the same antigen comes along again)
2. Immune response after primary immunization:
   - no detectable antibodies
   - a small burst of IgM antibodies occurs first
   - a small burst of IgG antibodies follows
3. Immune response after second, third, and booster shots:
   - almost immediate response due to activation of memory cells
   - a small burst of IgM
   - a large burst of IgG provides protective levels of antibody

Question 7

TITER

Answer 7

How much antibody is present

Question 8

Factors Affecting Response to Immunization

Answer 8

1. Differences in immune response by host
   - inheritance
   - diseases affecting immune system
   - general health
2. Site of injection
   - type of tissue
   - fat may absorb antigen so it does not reach B cells
3. Immunization product
   - manufacturers striving to improve vaccines and toxoids to give better immune response and fewer adverse reactions
4. Product failure
   - bad batch from manufacturer
   - improper storage may inactivate

Question 9

Products used for immunization

Answer 9

1. Vaccine: suspension of bacteria or virus, altered so not able to cause disease but still antigenic… causes production of antibodies
   Ex. Pertussis vaccine, measles vaccine
2. Toxoid: bacterial exotoxin treated so no longer toxigenic (harmful) but still antigenic… causes production of antibodies
   Ex.diptheria toxoid, tetanus toxoid

Question 10

Types of immunity

Answer 10

1. Artificially acquired
   - product given for the purpose of providing immunity… usually means a needle
2. Naturally acquired
   - an act of nature such as having a disease or antibodies transferred from mom to baby
3. Passive immunity
   - host given preformed antibodies
   - protection available immediately
   - used for disease treatment and occasionally short term prevention
4. Active immunity
   - host makes own antibodies when given or exposed to antigen
   - antibodies not available for days or weeks (takes longer if this is first exposure to antigen)
   - used for disease prevention… long term

Question 11

EXAMPLE OF USING THE TERMS OF IMMUNITY

Answer 11

The immunity of a child following chicken pox is naturally-acquired active immunity.

The immunity of a child following the pertussis vaccine is artificially-acquired active immunity.

The immunity from an injection of tetanus immune globulin is artificially-acquired passive immunity.

The immunity of a new born to infectious microbes is naturally- acquired passive immunity.

Question 12

Routine immunization schedule- nothing until 2 months old

Answer 12

• diptheria, pertussis, tetanus (DPT)
• polio
• haemophilus influenzae type B (Hib)- can cause meningitis
• MMR- measles, mumps, rubella
• chicken pox
• meningococcal conjugate
• pneumococcal conjugate
• hep B
• yearly influenza

Booster shots: diphtheria and tetanus every ten years

Question 13

Symptoms of Rubella (german measles)

Answer 13

• mild infection, rash (head, face, neck, trunk) for 2-3 days
• many cases subclinical (no symptoms)

Question 14

Danger of rubella during pregnancy

Answer 14

• virus can cross placenta to infect fetus
• fetus may be aborted or still born
• may be defects

Question 15

Immunization of rubella

Answer 15

• vaccine containing rubella virus (MMR= measles, mumps, rubella)
• part of childhood series; preferably before puberty
• do not immunize if pregnant or expecting to become pregnant within 3 months
• immunize males and females to eliminate viral reservoir
• law in some provinces that all health care workers have immunity to rubella

Question 16

Immunization against Hepatitis B

Answer 16

• all health care worker at risk of exposure to blood or fluids capable to transmitting infection should be immunized
• schedule: three shots of hepatitis vaccine (first two are one month apart, third is six months after first)
• protective level of antibodies after 3rd shot
• successful immunization: blood test for antibodies… anti HBs
• booster: under review… may be required after 5 years if antibodies lacking

Question 17

Hepatitis Immune Globulin (HBIG)

Answer 17

• passive immunization product with preformed antibodies
• given after a blood or mucous membrane exposure to hepatitis B virus when there is no evidence of anti-HBs in the health care worker
• provides show term protection for the incident… must be given within 48 hours

Question 18

Chicken pox virus (varicella-zoster) causes:

Answer 18

Chicken pox: generalized infection-fever, malaise, and vesicular eruptions

• spread by respiratory secretions or contact with vesicular fluid
• 2-3 weeks incubation period
• more sever in adults than children

Shingle: reactivation of the latent virus in older and immuno compromised patients

• causes painful eruptions in nerve endings, often a round waist
• a person cannot get shingles without previously having chicken pox

Question 19

Measures to reduce risk of chicken pox to patients

Answer 19

Chicken pox can be a serious threat to immunodeficient patients.

• determine immune status of health care workers in advance
• immunization of non-immune health care workers
• non-immune health care worker exposed to chicken pox should not be around immuno compromised patients from day 10-21 following exposure

Question 20

Why tuberculosis currently is a serious problem

Answer 20

• increase in the number of people infected and diseased

- emergence of drug-resistant strains

Question 21

How is tuberculosis spread

Answer 21

• direct contact with respiratory secretions

- droplet nuclei: the particles are too small to be trapped by cilia lining the respiratory tract

Question 22

Sequence of events following inhalation of tubercle bacilli

Answer 22

• bacteria multiply slowly in the lung for 3-6 weeks
• cellular immune system becomes activated during this time
• spread of bacteria halted-walled off by a group of cells- called a granulonmata
• person is infected but does not get disease and is not contagious

Question 23

Incidence of tuberculosis

Answer 23

• only about 5% of those infected develop TB

- another 5-10% of those infected may develop disease later in life when the immune system breaks down

Question 24

Symptoms of tuberculosis

Answer 24

• initially vague…persistent cough; fever of unknown origin
• later… bloody sputum, organ dysfunction

Question 25

Tuberculin skin test

Answer 25

- Intradermal injection in forearm of solution containing tubercle protein - read in 48 hours for raised, hard area - this is not a vaccine

Question 26

Reasons for positive tuberculin skin test

Answer 26

- person currently has tuberculosis - person had tuberculosis in past - person inhaled bacteria; infected but not disease (5% may develop disease later in life) - person has been immunized against tuberculosis (BCG vaccine)

Question 27

When tuberculin testing is done

Answer 27

- at start of employment in health care - on a regular basis following initial testing - following a known exposure