• Incidence: 150.00 cases per 100,000 person-years
  • Peak incidence: 40-50 years
  • Sex ratio: 1:1
Condition Relative
Carbon monoxide poisoning0.02
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Clinical features

The following are typically seen:


Consider prescribing antiviral treatment for influenza if all of the following apply:
  • 1) The patient is in an at-risk group* or is felt to be at risk of developing a serious complication
  • 2) There is circulating influenza nationally
  • 3) The patient is able to start treatment within 48 hours from the onset of symptoms (36 hours for zanamivir)

Antivirals for influenza
  • First line: oseltamivir
  • Second line: zanamivir
  • For immunocompromised adults and in renal impairment: zanamivir

*Chronic disease of respiratory, cardiac, renal, hepatic or neurological nature, diabetes, immunosuppression or have morbid obesity.


The overall case-fatality rate for influenza is around 0.1%.