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inclusion CRITERIA

  • Aged 6 months to 12 years inclusive.
  • In ‘at risk’ category
  • Presenting with influenza-like illness (i.e. cough and fever) during influenza season 
  • Presenting within 5 days of symptom onset
  • Permanently registered at a general practice in England
  • Parent /guardian able to complete study diary and questionnaires

FEVER defined as : symptom reported by parent, carer or child OR temperature measurement of 37.9°C or higher. 


The following ‘at risk’ categories are intended to guide clinicians in identifying which children are likely to be at greater risk of influenza-related clinical deterioration or complications.  However, healthcare professionals should also use their own clinical judgement to identify ‘at risk’ children and may discuss children whom they think may be ‘at risk’ with a medically qualified member of the research team.


  • Asthma requiring continuous or repeated use of controller therapy (e.g. inhaled steroids, leukotriene receptor antagonists, long-acting beta agonists, systemic steroids)
  • Admitted to hospital with exacerbation of asthma within the last 12 months
  • Admitted to hospital with bronchiolitis within the last 12 months
  • Recurrent viral wheeze (3 or more episodes within the last 12 months)
  • Bronchopulmonary dysplasia


  • Congenital heart disease being actively managed or monitored by cardiology team
  • Chronic heart failure being actively managed or monitored by cardiology team


  • Chronic neurological or neuromuscular disorder which compromises respiratory function (e.g. cerebral palsy)


  • Chronic kidney disease defined as either of the following: 1) Impaired eGFR (estimated glomerular filtration rate) measurement within the last 12 months or 2) known hereditary or structural kidney abnormality with or without impairment in eGFR
  • Nephrotic syndrome
  • Kidney transplantation

Impaired eGFR is defined as an eGFR measurement of 59 ml/min/1.73m2 or less within the last 12 months before study entry.  However, to enter the trial the following two conditions must also be satisfied:

  1. eGFR >=30 ml/min/1.73m2 based on most recent measurement within the last 12 months
  2. no reason to suspect further deterioration in eGFR at time of study entry


  • Cirrhosis
  • Biliary atresia
  • Chronic hepatitis

Children with mild or moderate liver disease may enter the trial.  Children with severe liver disease may not enter the trial.  Severe liver disease is defined as hepatic impairment associated with any of the following: jaundice, impaired coagulation/increased bleeding risk, bilirubin persistently greater than 50 micromol/litre (two measurements within last 12 months)


  • Asplenia or splenic dysfunction
  • HIV infection
  • Undergoing chemotherapy leading to immunosuppression
  • Taking systemic steroids at a dose equivalent to prednisolone 20mg or more per day (any age) or >=1mg per kg per day (children under 20kg)


  • Diabetes mellitus (type 1 or type 2) or other metabolic condition
  • Genetic abnormality (e.g. Down’s syndrome)
  • Sickle cell disease
  • Malignancy
  • Prematurity (born before 37 weeks gestation) in children aged 6 to 23 months