59. Vaccines Bacterial & Viral

Question 1

MenB vaccine

Answer 1

• 1999: conjugated group C, A, W and Y, as infants are not very good at detecting polysaccharides.
• 2015 MenB introduced in 2015. - given to newborns, 2-4 months and booster at 12 months.

ISSUES:

• 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

Question 2

Haemophilus influenza type B

Answer 2

Paediatric disease - usually 6 mo - 3 yrs 1/600
Initially, a nasopharyngitis (often starting with viral infection)
- spreads to an otitis media, sinusitis, bronchitis, pneumonia or sometimes epiglottitis (requiring a tracheotomy):- croup

• Spreads : bacteraemia, septic arthritis, meningitis (60% cases)
• Neurological disorders (33%) or death (5%) if not vigorously treated

=> Prevention of Hib meningitis and infections
•Vaccine effective: (99% cases are type b)
•type b - capsule polysaccharide linked to conjugate: - diphtheria/tetanus toxoids + outer membrane proteins

Question 3

Diphtheria

Answer 3

Corynebacterium diphtheriae

Pharynx - 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
• local inflammation ,swelling, lymph nodes ~ Bull Neck
• Respiratory obstruction