Vaccines - Bacterial & Viral Flashcards

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1
Q

What is the importance of immunisation schedules

A
  • Keeps booster vaccines up to date to keep protection
  • Live attenuated vaccines don’t need boosters as they are generally single-dose
  • Increase vaccine coverage
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2
Q

Describe the vaccines for meningitis in the UK

A
  • ## It is classified into different types according to the structure of the polysaccharide coat. Six serogroups responsible for almost all disease in world A, B, C, W-135, X, Y
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3
Q

What are the current MenC vaccine available in the UK

A
  • HiB/MenC combined vaccine given at 1 year. tradename Menitorix. MenC is conjugated bacterial polysaccharide conjugated to tetanus toxoid
  • Men ACWY – 14 years. Two available in UK tradenames Menveo and Nimenrix. Menveo consists of polysaccharides from A,C,W-135, Y conjugated to diptheria toxoid.
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4
Q

Why is it hard to develop a MenB vaccine

A
  • Very difficult to develop because polysaccharides are too similar to that on some human cell
  • A vaccine was developed in 2015
  • Maybe not cost effect for mass vaccination
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5
Q

Describe the Hib vaccine

A

Type b capsule polysaccharide linked to conjugate:-
either diphtheria or tetanus toxoids or meningococcal outer membrane proteins

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6
Q

Describe the effects of diphtheria pathogen which is vaccinated by DTP

A
  • Inhibits protein synthesis in eukaryotes
  • Pharynx, larynx, nose - non-invasive multiplication
  • Toxin produced locally but acts at a distance
  • absorbed by lymphatics - systemic effects
  • damages heart, kidney, nerves, adrenals
  • kills epithelial cells and polymorphs
  • gelatinous exudate ulcer - necrotic exudate - Pseudomembrane
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7
Q

How does the vaccine work to prevent diphtheria

A
  • Diphtheria toxin treated to make the toxoid which is not toxic but is immunogenic
  • Combined with aluminium salts adjuvant
  • Given as combined vaccine DTaP or dTaP (D = higher amount of toxoid)
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8
Q

Describe the effects of tetanus pathogen which is vaccinated by DTP

A
  • Caused by Clostridium tetani which is gram +ve rods, that exist within soil
  • Tetanus toxin is a neurotoxin that inhibits the release of neurotransmitters (GABA, glycine) from inhibitory interneurons, which interact with motor neurones, resulting in violent spastic paralysis.
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9
Q

How does the vaccine work to prevent tetanus

A
  • Tetanus toxin is treated with formaldehyde to convert it into a toxoid, loss of toxicity but not immunogenicity
  • Combined with aluminium salt adjuvant
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10
Q

Describe the effects of pertussis pathogen which is vaccinated by DTP

A
  • Severe cough lasting weeks often with a ‘whoop’ noise. Cough can last for weeks. WC can result in death especially in newborns
  • Bacterium adheres to ciliated epithelial cells in upper respiratory tract and multiplies. In infants may descend to lungs
  • Secretes pertussis toxin which is a virulence factor in pathogenesis of the disease and causes many of systemic symptoms including profound leukocytosis
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11
Q

How does the vaccine work to prevent pertussis

A
  • Old vaccine: Whole cell killed vaccine - reactogenic (fever, headaches, redness), concerns over efficacy in some countries and lingering concerns over link with brain damage
    The new vaccine is an acellular vaccine which contains pertussis toxoid
  • Blocks adhesion and neutralises toxin
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12
Q

What are the main aims of the Influenza programme

A
  • To protect those who are most at risk of serious illness or death should they develop influenza
  • To reduce the circulation of the virus
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13
Q

Who are vaccinated against influenza

A
  • all those aged 65 years or over
  • all those aged 6 months or over in a clinical risk group
  • those living in long-stay residential facilities
  • those who care for elderly or disabled persons
  • household contacts of immunocompromised individuals
  • those working within health and social care settings
  • pregnant women
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14
Q

What is influenza

A
  • RNA virus with 3 types and multiple serotypes
  • Surface glycoproteins Haemagglutinin
    (H/HA) and Neuraminidase (N/NA)
  • Seasonal flu – yearly, up to half a million
    deaths
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15
Q

What Influenza types mostly cause disease

A

Types A and B

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16
Q

What is the flu vaccine comprised of

A
  • Vaccines are usually quadrivalent containing two sub-types of Influenza A and 2 of Influenza B
  • Vaccine will change each year based on WHO recommendation for predominant circulating strains
  • All but one vaccine in UK are inactivated. Grown either in embryonated hens’ eggs or in cell culture and then inactivated
17
Q

What is the efficacy of the flu vaccine

A
  • variable by year/age group
  • antigenic drift and shift – mismatch between vaccine and circulating disease can reduce effectiveness of vaccine in some years
  • manufacturing issues can occur. May be tight schedule between WHO recommendations for vaccine and the beginning of flu season
18
Q

List the potential symptoms of streptococcus pneumonia

A
  • Menigitis
  • Otitis media
  • Pneumonia
  • Peritonitis
  • Arthritis
  • Soft tissue infection
  • Sinusitis
19
Q

Describe the PPV23 pneumococcal vaccine

A
  • A polysaccharide vaccine
  • The polysaccharides from 23 serotypes used in vaccine (PPV)
    for at risk adults and children over the age of 2
  • Children under 2 can’t make a long-lasting protective immune response to polysaccharide vaccines so they need a conjugated vaccine
20
Q

Describe the PCV13 pneumococcal vaccine

A
  • Polysaccharides from the 13 most common capsule types Conjugated to diphtheria toxoid
  • Estimated that the capsular types in the vaccine cause ~66% of all pneumococcal disease cases and 82% of pneumococcal disease in under five year olds
21
Q

Describe HPV as a pathogen

A
  • Over 40 types
  • HPV causes Genital Warts
  • High risk types (serotypes 16,18) – lead to cervical cancer, HPV16: 50%, HPV18: 20%
  • Low risk types (6,11) - warts
  • Before vaccine cervical cancer killed ~1000 women in UK each year (~ 3,000 cases p.a. in UK)
  • 1% of women cancer deaths
22
Q

What are the vaccines present against HPV

A

Two licensed vaccines:

  • Cervarix: protects against HPV 16,18
  • Gardasil : protects against HPV 6,11,16,18 - used now. Protects against genital warts and cervical cancer.
23
Q

What is the efficacy of the HPV vaccine

A
  • 66% reduction in prevalence high grade pre-cancerous lesions * 76% reduction in cervical cancer deaths * Will save 400 lives/year
24
Q

What is the schedule of the HPV vaccine

A

2 doses offered to boys and girls 12-13 yrs old

25
Q

What vaccines are available for pregnant mothers

A
  • Tetanus, Diphtheria, Pertussis/Polio introduced in 2012 for protection from whooping couch
  • Flu
26
Q

How is TB diagnosed

A
  • Diagnosed with the Mantoux test
  • Also called the PPD (Purified protein derivative) or tuberculin skin test
  • Skin injected with PDD of tuberculin and measured after 72h
  • If there is a reaction a bump will form on the skin
  • Results need to be interpreted carefully
27
Q

Should chickenpox be vaccinated against

A
  • In the Uk, we don’t vaccinate
  • Unless you are immunocompromised or a key healthcare worker
  • Could prevent shingles in the future