Influenza

Statutory notification alert

• Influenza viral infection is a notifiable infectious disease in Western Australia.
• See notifiable communicable disease case definitions (Word 1.29MB).
• Notifications should be made using the communicable disease notification form for metropolitan residents (PDF 214KB) or regional residents (PDF 213KB).
• For notification of regional residents see contact details of public health units (Healthy WA).
• See also description of Statutory medical notifications in Western Australia.

Public health management

Important information

• Infectious agent: Influenza virus, mainly types A, B and C and many subtypes and strains.
• Transmission: Influenza viruses are mainly spread by droplets made when an infected person coughs or sneezes. Influenza can also be spread through touching surfaces where infected droplets have landed.
• Incubation period: Usually 1 to 3 days.
• Infectious period: People with influenza can be infectious from the day before their symptoms start. Adults are most infectious in the first 3-5 days of their illness, while children remain infectious for 7-10 days, and people with weakened immune systems may be infectious for longer.
• Case exclusion: Recommend cases exclude themselves until symptoms resolve.
• Contact exclusion: Do not exclude.
• Treatment: Generally bed rest and symptomatic treatment. Specific influenza antiviral medicines can reduce the severity and the duration of influenza if taken soon after onset of symptoms.
• Immunisation: Annual influenza vaccination is recommended for all people aged > 6 months. It is strongly recommended, and free, through the National Immunisation Program and WA state-funded programs for: children aged > 6 months up to 5 years; Aboriginal and Torres Strait Islander people aged > 6 months; pregnant people; people aged ≥65 years, healthcare workers and people with certain health conditions; See Influenza Immunisation, Western Australian Immunisation Schedule and Australian Immunisation Handbook.
• Case follow-up: Public health action focuses on outbreaks in high-risk settings such as health care facilities, special schools, residential care facilities, and Aboriginal communities.

Guidelines

• Influenza infection national guidelines for public health units (external site)
• National Guidelines for the Prevention, Control and Public Health Management of Outbreaks of Acute Respiratory Infection (including COVID-19 and Influenza) in Residential Care Facilities (external site)
• Communicable Disease Guidelines, for teachers, child care workers, local government authorities and medical practitioners (PDF 386KB)
• Western Australian Immunisation Schedule (PDF 197KB)
• Australian Immunisation Handbook, Department of Health – Influenza (flu) (external site)

Notifiable disease data and reports

• Notifiable infectious disease dashboard
• General infectious disease reports

Further information

• Influenza (flu) vaccine (HealthyWA)
• Influenza (flu) vaccine – what pregnant women need to know (HealthyWA)