Clinical Practice Guidelines

Influenza - possible H1N1

  • Recommended  management of possible H1N1 influenza presenting to the emergency department of the RCH.

    RCH case definitions

     Adults and Children > 12 months old1 with

    measured temperature >38.5C or
    significant history of fever (with rigors, sweating chills)

    plus two or more of:

    • cough,
    • sore throat,
    • body aches,
    • fatigue/tiredness 
    • shortness of breath.

    But excluding patients with acute wheezing illnesses2
    (asthma, bronchiolitis, virus associated wheezing)


    1   See below for advice regarding babies less than 12 months of age.
    2   Previous surveillance studies have suggested a low rate of influenza as a cause of acute wheezing illnesses in children.

    This case definition is used to detect those with higher likelihood of influenza infection and/or higher likelihood of more severe infection / complications.
    It is not intended to detect all cases of influenza because there is no longer an aim to contain the spread of the virus in the general community.

    Risk factors for more serious disease

    Indigenous people

    Chronic illness:

    • pulmonary (including persistent asthma),
    • cardiovascular,
    • renal,
    • hepatic,
    • hematological (including sickle cell disease),
    • neurologic,
    • neuromuscular, 
    • metabolic disorders (including diabetes mellitus)
    • Immunosuppression, including that caused by medications, asplenia
    • Long-term aspirin therapy


    For patients well enough to be discharged home

    No viral investigations are needed.

    Recommend patients stay at home until symptoms have resolved.

    Most patients do not require oseltamivir.

    Give oseltamivir (treatment) if patient has  risk factors for more serious disease.

    Recommend oseltamivir (prophylaxis) for family members (via LMO) if they:

    Oseltamivir is given:

    • twice daily for 5 days to treat patients
    • once daily for 10 days for prophylaxis

    Since Victoria moved to the PROTECT phase for influenza - Oseltamivir is now only available on prescription.

    Dosing details here

    RCH information for families

    For unwell patients being admitted to hospital

    For all patients with symptoms suggestive of viral respiratory infection (excluding acute wheezing illnesses or more severe croup - risk of precipitating airway obstruction):

    • Take nose and throat swabs (using flock swabs) or a nasopharyngeal aspirate (for infants) - this will aid in infection control decisions on wards.
      (Note patients DO NOT need to remain in ED whilst awaiting swab results)
    • Isolate (or cohort) patients fulfilling the  case definition, or if subsequently shown to have influenza A.
      Other patients can be isolated (or cohorted) according to usual clinical practices.
    • Give Oseltamivir twice daily to treat admitted patients fulfilling the  case definition, or if subsequently shown to have influenza A.
    • Consider Oseltamivir treatment for unwell patients with risk factors for more serious disease even if they don't fulfill the strict case definition.

    Recommend oseltamivir (prophylaxis) for family members (via LMO) if they:

    For infants <12 months of age

    Oseltamivir has not been widely tested in children of this age group.

    If the patient does not require hospitalisation generally Oseltamivir should not be prescribed.

    For hospitalised infants meeting the case definition - Oseltamivir may be considered, particularly for those with chronic illness.

    Clinical judgement should be applied to balance the unknown risks of Oseltamivir vs the risks of influenza in those with chronic illness.

    Other infection control issues

    Staff with symptoms suggestive of viral respiratory illnesses (including flu-like illness) should seek advice from their LMO.

    In-hospital exposure

    Significant exposure is classified as being within 1 metre > 15 mins without personal protective equipment.

    Patients with  risk factors for more serious disease who have significant exposure should receive oseltamivir prophylaxis.
    Cohort exposed patients for 3 days, if on oseltamivir, or for 7 days if not taking prophylaxis.

    Staff who have significant exposure (not using PPE) should be offered oseltamivir prophylaxis. 
    Well staff taking prophylaxis do not need to be quarantined.

    Ideally, staff who have had a significant exposure should avoid high risk patient areas (the intensive care unit, haematology/oncology units, neonatal wards) for 3 days.  This however may not be practicable. Thus, following a significant exposure, a health care worker in these areas should have oseltamivir prophylaxis and can continue to work unless they become unwell.

     'Vulnerable settings'

    • child care centres with baby rooms (under 12 months of age)
    • special schools
    • aged care facilities
    • supported residential services (SRSs)
    • hospitals