Immunization and Disease Prevention Flashcards

1
Q

What does WHO say is the 2 public health interventions that have the greatest impact?

A
  1. clean water
  2. vaccines
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2
Q

Aim for the Malawi Expanded Programme on Immunization (EPI)?

A

Aims to decrease childhood morbidity and mortality from vaccine preventable diseases
- It is largely based on the WHO-recommended immunization schedule and guidelines

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3
Q

What is an immunization?

A

It is the process of inducing immunity against a specific disease

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4
Q

What are the types of immunity?

A
  1. passive(through administration of antibody)
  2. active(antigen or toxoid administration)
    - Produces a prolonged humoral and/or cellular immune response
    - Vaccines can be whole or parts of microorganisms
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5
Q

What are the types of vaccines?

A
  1. bacterial vaccines
  2. viral vaccines
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6
Q

What are bacterial vaccines?

A
  1. Whole organism e.g., inactivated oral typhoid vaccine
  2. Inactivated toxins e.g., diphtheria and tetanus vaccines
  3. Specific antigens e.g., Haemophilus influenzae b and pneumococcal polysaccharide vaccines
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7
Q

What are viral vaccines?

A
  1. Attenuated live viruses e.g. measles, polio and rotavirus vaccines
  2. Viral components e.g. hepatitis B vaccines
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8
Q

What is Bacillus Calmette-Guerin (BCG)?

A
  • Freeze-dried live attenuated strain of Mycobacterium bovis
  • Limited effectiveness in preventing pulmonary tuberculosis (about 50% efficacy)
  • More (80%) effective against milliary and meningeal TB
  • Contraindicated in symptomatic HIV infection (AIDS) or immunosuppressive conditions
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9
Q

What is the measles vaccine?

A
  • Attenuated virus
  • The WHO recommends immunization at nine months
  • Earlier immunization (e.g at six months) would have limited immunogenicity
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10
Q

What is pneumococcal conjugate vaccine (PCV)?

A
  • Includes the 13 of the 93 pneumococcal serotypes
  • Three doses given at 6, 10 and 14 weeks
  • Less efficacious in HIV-infected children (65% vs 83%) in reducing invasive pneumococcal disease
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11
Q

PCV has resulted in?

A
  1. Reduction in hospitalization for all cause pneumonia (30—40%)
  2. Reduction of acute otitis media in middle and high income countries (15-40% )
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12
Q

What is hepatitis B vaccine?

A
  • Recombinant hepatitis B vaccine provided at 6,10,14 weeks
  • Infants born to HBsAg+ mothers should receive both 0.5ml HepB immunoglobulin within 12 hours of birth and hepatitis B vaccine
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13
Q

Describe the Hemophilus influenzae type b (Hib) vaccine?

A
  • Is part of a multi-component vaccine (DPT-HepB-Hib)
  • Protects against epiglottitis, Hib meningitis, pneumonia, and osteomyelitis
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14
Q

What is the impact of Hib?

A
  1. has reduced invasive hib disease ( > 90%)
  2. Has reduced radiographically proved pneumonia (20-25%)
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15
Q

Describe the pertussis vaccine?

A

used against whooping cough

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16
Q

Describe the Diptheria toxoid vaccine?

A
  • Highly effective in inducing antibodies that neutralize toxin, thus protecting against diptheria
  • It may not protect against acquisition or carriage of Corynebacterium diptheriae
17
Q

What are the 2 kinds available for polio routine immunization?

A
  1. Inactivated polio vaccine (IPV)
  2. Live attenuated oral polio vaccine (OPV)
18
Q

Describe the OPV polio vaccine?

A
  • Rare (1/2,000,000) risk of causing vaccine-associated paralytic poliomyelitis
  • Induces greater mucosal immunity than IPV
19
Q

Describe the Rota virus?

A
  • Live attenuated vaccine provided at 6 week and 10 weeks
  • Slight increased risk of intussusception with rota virus vaccine use
20
Q

Malawi immunization schedule?

A
  1. at birth
    - BCG, OPV 0
  2. 6 weeks
    - OPV 1, Rota 1, Pentavalent 1, PCV 1
  3. 10 weeks
    - OPV 2, Rota 2, Pentavalent 2, PCV 2
  4. 14 weeks
    - OPV 3, Pentavalent 3, PCV 3, IPV
  5. 5 months
    - MV 1
  6. 6 months
    - MV 2
  7. 7 months
    - MV 3
  8. 9 months
    - MR 1
  9. 15 months
    - MR 2
  10. 22 months
    - MV 4
21
Q

HPV vaccine vaccination (9 year old girls) schedule?

A

9 years
- HPVV 1, HPVV 2 (6 months after HPVV 1)
- Intra muscular
- upper arm
- 0.5 ml
Note: HPV is major causes of cervical cancer in women and laryngeal papilloma in children

22
Q

Td vaccination (women of child bearing age) schedule?

A

15 - 45 years
- Td 1 at contact
- Td 2 (1 month after Td 1)
- Td 3 (6 months after Td 2)
- Td 4 (1 year after Td 3)
- Td 5 (1 year after Td 4)
> intra muscular
> right upper arm
> 0.5 ml

23
Q

Established vaccine not included in the Malawi EPI program?

A
  1. Measles, Mumps and Rubella (MMR) - Malawi has the MR component
  2. Influenza vaccine
  3. Hepatitis A
  4. Varicella vaccine (attenuated vaccine - contraindicated in advanced immunosupressive disorders and in pregnancy)
  5. Meningococcal C vaccine
24
Q

Immunization practical considerations?

A
  1. Vaccines lose their potency if not stored and transported correctly
  2. Vaccines should be refrigerated between 2 °C and 8 °C
  3. The “cold chain” from manufacturer to administration of vaccines is a critical part of EPI
  4. Vaccines (except for freeze-dried BCG, OPV, MR) should not be frozen
  5. Diluent is never frozen
  6. Some vaccines (e.g BCG, MR) lose potency if exposed to light
  7. Reconstituted vaccines should be checked for signs of deterioration, such as a change in colour or clarity
  8. Reconstituted vaccines deteriorates rapidly at room temperature and should be used within 12 hours
25
Q

Contraindications to vaccines?

A
  1. Anaphylactic reaction to a prior dose (vaccines grown in eggs, gelatin stabilizers; antimicrobial agents)
  2. Defer vaccine in moderate to severe acute illnesses - mild illness may be vaccinated
  3. Children receiving corticosteroids (≥2 mg/kg/day or ≥20 mg/day of prednisone or equivalent) for 14 or more days
  4. Malignant disease, immunosuppressive drugs
26
Q

Which immunodeficient conditions can be given live vaccines?

A
  1. HIV
  2. severe malnutrition
27
Q

Host risk factors for hospital acquired infections?

A
  1. Recent invasive procedures
  2. Presence of catheters or other devices
  3. Prolonged use of antibiotics
  4. Contaminated physical environment
  5. Exposure to people with active contagious infections (patients, visitors, or healthcare providers)
  6. Colonized with invasive microorganisms
  7. Anatomic abnormalities (dermal sinuses, cleft palate, obstructive uropathy)
  8. Abnormal skin
  9. Organ dysfunction e.g. heart failure, bone marrow suppression
  10. Malnutrition
  11. Underlying diseases or comorbidities
28
Q

How are recent invasive procedures risk factors for hospital acquired infections?

A
  1. Breaching normal anatomic host barriers
  2. Provide direct access to sterile anatomic sites
  3. Disrupt patterns of normally protective flow of mucus (e.g., nasotracheal tubes and sinus ostia)
    - Tubes placed through the nose may disturb function of cilia an obstruct drainage of sinuses
29
Q

How is prolonged use of antibiotics a risk factor for HAIs?

A

Can alter the composition of bowel flora and encourage the multiplication and emergence of toxigenic or invasive organisms (e.gClostridium difficileandSalmonellaspp)

30
Q

Agents of infection transmission?

A
  1. Thehands
  2. Medical equipment
  3. Toys
  4. Hospital and office furnishings
  5. Phones
  6. Computer keyboards
  7. Neckties
    - these inanimate objects serve as fomites
31
Q

Agents of airborne transmission?

A
  1. Varicella virus
  2. Measles virus
  3. Coronavirus
  4. Mycobacterium tuberculosis
32
Q

Describe handwashing?

A
  • Placing the hands under water and using friction with or without soap.
  • 15-second scrub removes the majority of transient, surface flora
  • Hand gels and rubs can be used in place of handwashing
33
Q

Describe waterless hand hygiene?

A
  • Preferred agents for routine hand hygiene when hands are not visibly soiled
  • Effectively kills most microbes but do not remove dirt or debris
  • Ineffective against nonenveloped agents such as norovirus andC. difficilespores
34
Q

Standard precautions in disease prevention?
Aims?

A

involve the use of barriers
e.g. gloves, gowns, masks, goggles, and face shields—as needed
- Aims to prevent transmission of microbes associated with contact with blood and body fluids