L32. Vaccine prevented diseases in kids

Question 1

What is the difference between live attenuated vaccine and inactivated vaccine and what are the different versions

Answer 1

1. Live attenuated means that the live virus or bacteria has been altered - but may replicate and cause local disease
2. Inactivated vaccines can be
   - whole virus/bacteria.
   - fractionated v/b:
   are either
   a) pure cell wall polysaccharide from bacteria or attached to a protein
   b) protein based: inactivated bacterial toxin, subunit, subvirion products

Question 2

What is the presentation/ time course of Measles and complications

Answer 2

1. 2-3 days of fever, conjunctivitis, coryza, Kopliks spots (buccal mucosa)
2. Characteristic rash day 3-7 where most unwell

Comp: 10% have a secondary infection: eg. ot med., pneumonia, croup

Question 3

What vaccine is against measles and when is it given.

What type of vaccine and what is the herd immunity target %

Answer 3

1. Priorix given at 12 and 15 months.
2. It is a live attenuated viral vaccine and 1 dose= 90% of ppl immunised.

Target is 95% of population/ as Reproduction number is high (15)

Question 4

What is the presentation of rash and fever in Parvovirus, Exanthem subitum Roseola (HHV 6), enteroviruses and EBV

Answer 4

1. P:’slapped cheek’ followed by fine lacey rash
2. HHV 6: High fever then sudden drop in fever and widespread rash as infant. Gets better
3. Ent: mild, common cause of rash.
   - Some neurotropic causing viral meningitis
   - coxsackie subtypes cause hand, foot mouth painful blisters.

4.EBV: Glandular fever + rash if given B-lactams

Question 5

How do you investigate a child/infant with fever and rash if immunised

Answer 5

1. If well-looking, may not find a cause and likely not require additional investigations.
2. Otherwise assess how unwell child is
   - current epidemiology of infectious diseases
   - vaccine status of individual and population

Question 6

What does ‘irritability’, tense fontanelle and stiff neck mean as signs in children

Answer 6

Irritability: possible neurological cause
Tense fontanelle: increased intracranial pressure - meningitis?
Stiff neck: sign of meningitis

Question 7

What are the 3 bacterial pathogens that cause meningitis (inflammation of the meninges) in infants and their gram stain/ shape

(different pathogens occur at different ages)

Answer 7

1. Strep pneumoniae (gram + cocci)
2. Neisseria meningitidis (gram - cocci)
3. Haemophilus influenzae (gram - bacili)

NB: Viral agents also cause; herpes simplex, enterovirus. +TB

Question 8

What type of vaccine is used to give to protect against bacteria causing meningitis for kids under 2 and why.
- give specific vaccine eg

Answer 8

Polysaccharide antigens alone produce a very weak antibody response/ poor immunological memory.
SO Conjugate vaccine: A polysaccharide attached to carrier (immunogenic) protein is used.

This is taken up by B cells and presented to Tcd4 cells, which converts it into a T cell dependent antigen, leading to good production of memory cells. + reduces nasopharyngeal colonisation

• Hib, Meningococcal Pneumococcal vaccine

Question 9

How might Hib present (determined by Determined with blood culture and CSF culture from lumbar puncture. )

What is the vaccine for Hib and when is it given

Answer 9

1. Presents with fever, irritability, tense fontanelle.
2. No rash. May lead to seizures. Complications= hearing loss
3. Inactivated Hib antigen vaccine part of Hexavalent given at
4. 6 wks, 3 and 5 months. Booster at 15 months.

Question 10

How does Invasive pneumococcal disease present and what bacteria is the main cause
Major mortality <2yrs

Answer 10

1. Last 3 days: High fever, lethargy, coryzal,
2. No stiff neck.
3. Increased RR, HR then getting increasingly drowsy

This disease has pneumococci - Usually Streptococcus Pneumoniae isolated from usually sterile sites
- CSF (meningitis), Blood (bacteremia) or Pleural space/lung tissue (pneumonia)

Question 11

What are the vaccines for Streptococcus pneumoniae and when is it given/to who. What are the added benefits of it

Answer 11

Vax
1. Polysaccharide vaccine - capsular polysaccharide from 23 most common serotypes. More for immunosuppressed/chronic illness, splenectomy and elderly.

2. Synflorix conjugate vaccine given to 6wks, 5 and 12 months

Benefit is that it protects those not receiving the vaccine - common cause of pneumonia (>5 yold + adults)

Question 12

How does Meningococcal disease present (sepsis ver – also have meningitis), what is the main pathogen

Significant mortality

Answer 12

1. High fever, Increased HR, RR,
2. Normal fontanelle, no stiff neck
3. Poor capillary refill time: Sign of shock in children, increased drowsiness,
4. Rash rapidly develops

Commonly caused by Neisseria meningitidis: Polysaccharide capsule ABC most likely to cause meningitis (W135 and Y also important)

Question 13

What are the vaccines against meningococcal disease and which serogroups do they protect against and why

• strains of meningococcal can change all the time?

Answer 13

1. MENACTRA/Nimenrix: polysaccharide conjugate vaccine against A, C, W135 and Y. Funded for students living in shared accom, 2yrs old children
2. BEXSERO: using a combination of protein targets to create a new generation vaccine against B. This is because B capsule has same sugars found in immature human neural cells so have tolerance. Funded for risk groups
3. Neis Vac-C - against C type which free for infants <2yrs.

Question 14

What are the common reasons for caregivers not immunising their child

Answer 14

• Contraindications for immunising
• Barriers to access to healthcare
• Lower immunisation access and rates for Maori children. –Improved with appropriate recall/outreach systems in 1’ care.
• Hesitancy is not common.