Vaccines: Bacterial & Viral Flashcards
Name examples of common vaccines
Neisseria meningitidis group C, B and A, Y, W Haemophilus influenzae type b Streptococcus pneumoniae Influenza virus Tuberculosis (BCG) Tetanus, Diphtheria, Pertussis Measles, Mumps, Rubella Polio, Hepatitis B, HPV, VZV
Give examples of travel vaccines
Travel vaccines: cholera, travellers diarrhoea, HepA, yellow fever, typhoid
What are some common biodefence vaccines?
Biodefence: anthrax, plague, tularaemia, smallpox
Give examples of agriculture vaccines administered
Agriculture: avian flu, foot and mouth virus, rabies
When is the Men B vaccine given?
- All newborn babies
- 2 and 4 months; Booster 12 months
- Catch up programme for babies born after 1ST May 2015
- Other groups remain vulnerable – cost effectiveness, shortages of supply, JCVI
Describe the structure of the Men B vaccine
Bexsero® Components
Outer membrane vesicles (OMV)
- N. meningitidis group B strain Z98/254 menZB
- 3 Surface proteins (non-variant) of the bacteria – recombinant :
• Factor H Binding Protein (fHbp)
• Neisseria Heparin Binding Antigen (NHBA)
• Neisseria Adhesin A (NadA)
What are some of the issues surrounding the Men B vaccine?
- more reactogenic;
- not all serotypes of group B covered (unlike menC)
- Some cross-protection against menW
- £75 per dose – needs to be £20 for cost effectiveness.
- 88% efficacy and strain coverage
- Duration of protection – 10 years
What is meningitis ACWY?
Highly virulent invasive strain W
Increasing since 2009
Who is vaccinated against Men ACWY?
Vaccinate risk groups:
- 14 – 18 year olds (school year 13) and
- older university entrants (aged 19 - 25)
- serotype replacement following menC??
Why are live attenuated vaccines only given once?
Live attenuated viruses don’t require boosters
What is the DTaP vaccine for?
DTaP - Diphtheria, Tetanus and Pertussis
- toxoid virus given 3 times
What is the IPV vaccine?
IPV - inactivated poliovirus
- toxoid virus given 3 times
What is the Hib vaccine for?
Hib - haemophilus influenzae B vaccine (bacterial infection) also boosted
What is Hib?
Haemophilus Influenzae Type B
Paediatric disease usually 6 mo - 3 yrs
Incidence: 1/600
Describe the signs and symptoms of Haemophilus influenzae B
Initially, a nasopharyngitis (often starting with viral infection) spreads to an otitis media, sinusitis, bronchitis, pneumonia or sometimes epiglottitis (requiring a tracheotomy):- croup
What other infections are spread from haemophilus Influenzae B ?
Spreads :
- bacteraemia,
- septic arthritis
- meningitis (60% cases)
What are the consequences of untreated Hib?
Neurological disorders (33%) or death (5%) if not vigorously treated
How is Hib meningitis and other infections prevented?
Vaccine effective: (99% cases are type b)
Why are capsulated vaccines not effective in children <2 months
Capsules aren’t effective vaccines in children as they can’t make ab against polysaccharides so is conjugated
How are capsulated virus made effective for younger babies?
conjugated with polysaccharides e.g.
type b - capsule polysaccharide linked to conjugate:-
diphtheria/tetanus toxoids + outer membrane proteins
What bacterium causes diphtheria?
Corynebacterium diphtheriae
Where does the diphtheria localise in the body?
Pharynx - non-invasive multiplication
Which organs does diphtheria infection effect?
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
- Local inflammation ,swelling, lymph nodes - Bull Neck
- Respiratory obstruction
Describe the bacteria causing tetanus
Neurotoxin Clostridium tetani
- Gram +ve rods,
- terminal drumstick spores
- anaerobe
- Soil dweller
What is the effect of neurotoxins on the nervous system?
Blocks release of inhibitory transmitters GABA and glycine -> unopposed continuous excitation
Neurotoxins cause spastic paralysis causing lock jaw
How do vaccines act against neurotoxins?
By neutralising toxin we can prevent infection achieved via subunit toxoid vaccine (boosted)
Describe the DTaP vaccine
Multi-toxin disease
Whole cell vaccine - killed organisms: associated toxicity
Describe the new low risk DTa[P vaccine available
New low risk acellular vaccine: Adhesin + pertussis toxoids + outer membrane proteins
⇒ Blocks adhesion and neutralises toxin - antibody role, V. effective
What are the aims of the influenza programme?
To protect those who are most at risk of serious illness or death should they develop influenza
To reduce the circulation of the virus
Who is eligible for influenza vaccine?
- all 65 years or over
- all those aged 6 months+ in a clinical risk group
- those living in long-stay residential facilities
- elderly or disabled persons carers
- household contacts of immunocompromised individuals
- health and social care workers
- poultry workers
- all children 2 – 9 years (most infections and transmission source)
How many potential protein targets are there for the influenza vaccine?
Require neutralising antibodies targeting the surface proteins
H: hemagglutinin - 15 types
N: neuraminidase - 9 types
What are the 2 ways influenza variation can occur
Epidemics: Antigenic drift
– mutation + selection
Pandemics: Antigenic shift
– gene reassortment
What is the effectiveness of the latest flu vaccine?
- variable by year/age group
- antigenic drift and shift;
- prior exposure; cross-reacting antibodies
- Vaccine production issues
Outline the spectrum of pneumococcal infection
- SInusitis (common)
- Passive pneumococcal disease (bacteramia)
- Soft tissue infection (rare)
- Arthritis (rare)
- Peritonitis (rare)
- Pneumonia
- Otitis Media
- Meningitis
Which populations groups are mostly affected by ppneumoccoccal infections?
Disease burden mainly in young children (<1) and ageing population 70+
These populations are prone to lobar pneumonia as a result of pneumococcal infection
What factors determine who gets a vaccine?
- Community instance rates
- Age prevalence
- Surveillance of disease
Who is given the polysaccharide pneumonia vaccine?
- Pneumococcal Polysaccharide Vaccine PPV23
- 23-valent pneumococcal polysaccharide vaccine (PPV)
- for at risk adults and children over the age of 2
Why are children under 2 not given the polysaccharide pneumonia vaccine?
Children under 2 can’t make a long-lasting protective immune response to polysaccharide vaccines
These 23 types of bacteria cause about 96% of all pneumococcal disease cases in the UK
How are children under 2 vaccinated against pneumnia?
- Pneumococcal Conjugate Vaccine PCV-13V
- Polysaccharides from 13 most common capsule types
- Conjugated to T/D toxoids + OMP as for Hib and MenC
How many types of HPV are there?
Over 40 types
What are the different types of Genital warts (HPV)?
High risk types (16,18) – lead to cancer
- HPV16: 50%
- HPV18: 20%
Low risk types (6,11) - warts
What are the 2 HPV licensed vaccines?
Gardasil: protects against HPV 6,11,16,18 - used now
Cervarix: protects against HPV 16,18
What vaccines are commonly in vaccines?
Neonatal tetanus: Disease of 8th Day - 360,000 deaths/yr
Tetanus toxoid to mother in late pregnancy→ high titres of maternal IgG in neonate
Why are live attenuated vaccines not given during pregnancy?
Don’t want live vaccines during pregnancy: ?damage to foetus e.g. rubella (MMR)
What prophylactic vaccines are given during pregnancy?
- TdaP/polio - whooping cough - Boostrix IPV
2. Flu - mother and baby protection – earlier the better
Who is given a TB vaccine?
All infants living in areas where TB incidence is >40/100,000
All infants with a (grand)parent born in a country where TB incidence is >40/100,000
at risk secondary school children
Previously unvaccinated new immigrants from high prevalence countries for TB
