Bacterial and Viral Vaccines

Question 1

when it comes to meningococcal infections, why is there no cross protection?

Answer 1

because the different strains have antigenic variation

Question 2

which N.meningitidis strains have vaccines against them?

Answer 2

Group C and A, W and Y
- it is a conjugated capsular polysaccharide vaccine (conjugated because children under 2 don’t make antibodies against PLS)

no vaccine for type B before 2014 because the sugar in type B is also found in eukaryotic cells, so an antibiotic would’ve affect our cells too

Question 3

describe the Men B Vaccine (Sept 2015)

Answer 3

vaccine offered at 2 and 4 months followed by a booster at 12 months

you can reduce the incidence of the disease by vaccinating newborns and more vulnerable younger children - reduces infectious pool and herd immunity protects those that haven’t been vaccinated

this vaccine not as good as A and W vaccines, and didn’t give much cross reactive protection against other strains, only menW a bit

10 year duration of protection

Question 4

MenACWY conjugate vaccine

Answer 4

offers protection against the highly virulent invasive strain W

increasing since 2009, emerging strain in young adult population

Question 5

do live or dead vaccines require boosters?

Answer 5

dead ones

Question 6

Haemophilus influenza type B (HIB)

Answer 6

Paediatric disease - usually 6 mo - 3 yrs

Initially, a nasopharyngitis (often starting with viral infection)

spreads to sinusitis, bronchitis, pneumonia or sometimes epiglottitis (requiring a tracheotomy)

Spreads : bacteraemia,
septic arthritis,
meningitis

death (5%) if not vigorously treated

Question 7

Prevention of Hib meningitis and infections

Answer 7

very effective conjugated vaccine

capsule polysaccharide linked to conjugate - diphtheria/tetanus toxoids + outer membrane proteins

Question 8

Diphtheria

Answer 8

Toxin produced locally but acts at a distance - absorbed by lymphatics and has systemic effects - damages heart, kidney, nerves, adrenals

Death of epithelial cells

Pseudomembrane at the back of the throat, it’s a build up of exudate

local inflammation ,swelling, lymph nodes

Respiratory obstruction due to inflammation

Question 9

Tetanus

Answer 9

a neurotoxin disease

Blocks release of GABA/glycine at inhibitory synapse, locking of the muscles - unopposed continuous excitation, leading to spastic paralysis

vaccine works by generating neutralising antibodies against the toxin

Question 10

DTaP vaccine

Answer 10

tetanus, diptheria and whooping cough

acellular vaccine
adhesin + pertussis toxoids + outer membrane proteins

blocks adhesion and neutralises toxin - antibody role

very effective

Question 11

Influenza vaccine programme

Answer 11

the aim is to protect those who are most at risk of serious illness or death should they develop influenza

given to:

• 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 with immunocompromised individuals
• those working within health and social care settings
• those who work in close contact with poultry
• all children 2 – 9 years (most infections and transmission source)

Protect vulnerable people by vaccinating people around them to prevent transmission

Question 12

what does the influenza virus target and what are the complications with this vaccine?

Answer 12

neutralising antibodies that target the haemaglutinin molecules on virus surface

flu virus undergoes antigenic drift – the gradual accumulation of mutations in the haemaglutinin genes, epidemic

OR antigenic shift, recombination of viruses can occur - acquire a new gene for a new haemaglutinin molecule that’s never been seen before in a population for many years – puts a population at risk, pandemic

Question 13

Invasive Pneumococcal infection - who does it affect most?

Answer 13

mainly young kids and older people

Question 14

types of pneumococcal vaccine?

Answer 14

1. Pneumococcal Polysaccharide Vaccine PPV23
   - for at risk adults and children over the age of 2
   - kids under 2 can’t make a long-lasting protective immune response to polysaccharide vaccines
2. Pneumococcal Conjugate Vaccine PCV-13V
   - conjugated to T/D toxoids + OMP as for Hib and MenC
   - Vaccine 1. wouldn’t work for kids because they don’t recognise polysaccharides so a conjugated vaccine was made.

Question 15

Human Papillomavirus (HPV)

Answer 15

over 40 types

Genital Warts:-
High risk types (16,18) – lead to cancer

Low risk types (6,11) - warts

1% of women cancer deaths

Question 16

HPV Vaccination

Answer 16

Two licensed vaccines:

Gardasil: protects against HPV 6,11,16,18 - used now
Cervarix: protects against HPV 16,18

Clinical trials show high efficacy, well tolerated, very effective

only need 2 doses of the vaccine - it is a recombinant protein vaccine: made up of some of the capsid proteins, forms an artificial virus particle and proteins assemble

Question 17

Vaccination in Pregnancy

Answer 17

1. Neonatal tetanus: Disease of the 8th Day, tetanus causes death on day 8. therefore vaccinate pregnant women to protect newborns

Tetanus toxoid to mother in late pregnancy - live vaccines may damage foetus

2. TdaP/polio - whooping cough
3. Flu

Question 18

Mantoux test

Answer 18

widely usedtestfor latent TB

injecting small amount of a substance called PPDtuberculininto the skin of your forearm