Norovirus

Question 1

Norovirus immunocompromised patients

Patient norovirus positive.

Symptoms start to resolve.

When can we say infection is cleared?

Answer 1

Immunocompetent - cleared when symptoms resolve, and have formed stool

Immunocompromised -
- needs 2x negative stool 1 week apart. If both negative, infection cleared
- if remains positive, but asymptomatic, this is considered chronic viral shedding

Question 2

Norovirus immunocompromised patients

Patient has ongoing diarrhoea

What alternative diagnoses to consider?

Answer 2

Chronic norovirus

MCS/ PCR for common targets - E.coli, Campylobacter/Crypto
C.difficile
Ova/Cysts/Parasites
CMV

Coeliac

Question 3

Norovirus immunocompromised patients

What are potential treatment options?

Answer 3

Reduce immunosuppression

Favipiravir - small number of patients shows benefit

Ribavirin - small set of data shows benefit

Nitazoxanide - small data that may be beneficial. Unclear mechanism. May help improve host viral response

Interferon-alpha

Immunoglobulins - may be beneficial if this is the primary immune disorder. Can be given NJ so immunoglobulins go to site of infection

Question 4

Norovirus immunocompromised patients

What is a suggested stepwise approach to treatment?

Answer 4

Reduce immunosuppression

Start favipiravir

Ongoing symptoms - start nitazoxanide

Ongoing symptoms - add Ribavirin

Ongoing symptoms - add interferon-alpha

Ongoing symptoms - consider bone amrrow transplant or NJ immunoglobulin

Question 5

What is dose of favipiravir?

Answer 5

Favipiravir 1200mg BD initially

Can be increased to 2400mg BD