Vaccines - Bacterial & Viral Flashcards
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
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
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.
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
5
Q
Describe the Hib vaccine
A
Type b capsule polysaccharide linked to conjugate:-
either diphtheria or tetanus toxoids or meningococcal outer membrane proteins
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
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)
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.
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
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
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
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
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
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
15
Q
What Influenza types mostly cause disease
A
Types A and B
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
