Astro/noro/rota/sapo Flashcards
Mum is on rituximab and receives a dose during pregnancy. Which vaccine(s) can’t the baby have?
“immunisation with live vaccines should be delayed until 6 months of age in children born to mothers who received immunosuppressive biological therapy during pregnancy. In practice, this means that children born to mothers who were on immunosuppressive biological therapy during pregnancy will not be eligible to receive rotavirus vaccine (and will need to defer BCG, if indicated, for 6 months). “
From chapter 6 green book
Which species of rota virus most commonly causes human infection?
Rotavirus A species based on VP6 protein. Further subclassified by G and P type using VP7 and VP4 respectively
Rotavirus vaccine -
type?
Recipients and schedule?
Contraindications?
Live attenuated oral vaccine
Given as 2 doses
-First dose at 8 weeks and not later than 15 weeks
- Second dose at 12 weeks and not later than 24 weeks
Dosing schedule designed to minimise possible risk of intussusception
Contraindications
- Mother received biological immunosuppression during pregnancy. (live vaccine CI for first 6 months)
- SCID
- child with hx intussusception
What timings can the the rota virus be given/not given?
First dose
- After 8 weeks and no later than 15
- Second dose 4 weeks after first and no later than 24.
Appearance of astrovirus on EM ?
28-30nm (small)
5 or 6 pointer star appearance.
- Not all virions (usually around 10% and pH dependent)
Genome of rota virus and EM appearance?
Looks like a wheel - rota = latin for wheel.
Genome - ds RNA gapped genome.
** the genome can rotate (antgenic shift) more than others**
Most common strain of norovirus in uk?
GII.17
Strain of norovirus associated with worse disease?
GII.4
Gene which confers resistance to norovirus infection?
Fut2 - occurs in around 20% of European descendants. Homozygotes don’t display h proteins in their gut which is required for some noro strains to infect (esp gii.4). H protein part of ABOH blood grouping proteins.
If you’ve got 2 feet (fut) you can outrun noro
Incubation and infectious period for noro
Incubation - short 12-48h
Infectious period - Symptom onset until 48h afterwards
Vaccine trials in uk for noro?
Type of vaccine and coverage?
mRNA-1403 – Moderna sponsored phase 2 trial underway in the UK. Trivalent mRNA-based candidate containing mRNAs that encode for the major capsid protein 1 (VP1) of three globally prevalent Norovirus genotypes—GII.4, GI.3, and GII.3.
HilleVax - VLP vaccine with phase 2 trials underway - contains antigens to GI.1 and GII.4 genotypes
What are the families of:
Norovirus
Rotavirus
Sapovirus
Astrovirus
Caliciviridae
Reoviridae
Caliciviridae
Astroviridae
What type of virus (+/- ss/ds) are:
Norovirus
Rotavirus
Sapovirus
Astrovirus
+ssRNA
dsRNA
+ssRNA
+ssRNA
Incubation periods of:
Norovirus
Rotavirus
Sapovirus
Astrovirus
12-48 h
1-2 d
1-4 d
1-4 d
What are the extra-GI manifestations of Astrovirus?
Encephalitis and meningitis (mostly) in immunosuppressed
How many genogroups of norovirus are there?
Which most cause human infect humans?
How are genotypes subdivided?
10
GI and GII
Based on G and P types (same as rota)
How long does norovirus shed in stool post infection?
Weeks in immunocompetent, even longer (up to years) in immunocompromised
Does asymptomatic infection pose a transmission risk in norovirus?
Yes, asymptomatic infection still results in high stool viral shedding
Which groups are most at risk of severe norovirus infection?
Infants
Immunosuppressed
Elderly
What are the extra-GI manifestations of norovirus?
Seizures in young children
Encephalopathy
Acute liver disease
What patients are at risk of chronic norovirus?
What are the symptoms?
What treatment have been used in chronic noro?
Immunocompromised
Malabsorption and wasting
Reduction of immunosuppression
Dietary interventions
Nitazoxanide
Ribavirin
Prednisolone
Favipirivir
What defines the end of a norovirus outbreak?
72 h after the last episode of vomiting or diarrhoea
What PPE should be worn when working with a patient with norovirus?
What additional PPE is required if there is a risk of splashes?
Gloves and aprons
Type IIR fluid resistance surgical mask and eye protection
What bleach is used for cleaning rooms of noro infected patients?
1000 ppm hypochlorite disinfection
When can norovirus infected patients be discharged to a nursing home?
At least 48 h since resolution of symptoms
How long do rotavirus symptoms persist? What are the symptoms? Which patients are most at risk?
Mild fever, watery diarrhoea, vomiting and dehydration
Last 3-8 days
Young children are most at risk
What are severe and rare symptoms of rotavirus?
Severe fluid loss and death
Febrile seizures
Rarely hepatitis (immunosuppressed children), CNS disease, chronic infection
Which vaccine is used in the UK for rotavirus?
Rotarix (GSK) since 2013
Which genotypes does the rotavirus vaccine protect against?
G1P8
G2P4
G3P8
G4P8
G9P8
How effective is the rotavirus vaccine at protecting against gastroenteritis?
85%
How long is there a risk of rotavirus vaccine strain transmission post vaccine? What is recommended for immunosuppressed contacts?
Possible vaccine strain transmission for 14 days
Advise hand hygiene for immunosuppressed contacts of vaccinated infants
When is rotavirus vaccine licensed from?
6-24 weeks
What strain is the rotavirus vaccine based on?
G1P8 which is most prevalent
How long does rotavirus shed in faeces?
Up to 7 weeks
What should be considered in infants in whom vaccine strain rotavirus is detected >7 weeks post vaccine?
Infants should be investigated for SCID
What is the infectious period of rotavirus?
1-3 weeks
