Seasonal influenza
Key Findings
The disease
Influenza, or ‘the flu’, is a respiratory illness caused by influenza type A and type B viruses. In winter, influenza epidemics usually occur. Pandemics (epidemics across many countries) can also occur when major changes in the virus occur. New strains of influenza viruses are continually evolving, which is why annual vaccination is recommended.
Transmission
Influenza is spread through droplets in the air from coughing and sneezing. It is highly contagious. The virus can land on tables and other surfaces and then transfer to people’s mouths and noses after they touch these surfaces. Children are more likely to spread the infection, as they are infectious for longer and have worse hand hygiene than adults.
Signs and symptoms
Symptoms can happen very quickly. Complications of influenza include pneumonia and asthma complications.
Common symptoms include:
- fever
- cough
- sore joints and muscles
- tiredness
- headache.
Vaccination recommendations and coverage
Seasonal influenza vaccine has been funded for all Aboriginal and/or Torres Strait Islander people aged 6 months and older since 2019.
Who is most affected?
While anyone can get influenza, those most at risk of developing complications or dying are:
- young children
- the elderly
- anyone with underlying medical conditions, such as lung disease, heart disease and diabetes.
How common is it?
There were a total 714,488 influenza notifications recorded for all ages combined across all states and territories during 2016–2019. Of these, 267,225 (37.4%) were in Aboriginal and/or Torres Strait Islander people. The influenza notification rate was significantly higher than in the previous reporting period, 2011–2015.
The highest age-specific notification rates were seen in the 6 months to <1 year age group; the notification rate for Aboriginal and/or Torres Strait Islander children in this age group was 2.4 times higher than for other children in the same age group.
Hospitalisations/deaths
During the 2016–2019 period, there were 112,252 hospitalisations for influenza, with 5,635 (5.0%) of these in Aboriginal and/or Torres Strait Islander people.
Rates of hospitalisation were higher for Aboriginal and/or Torres Strait Islander people across all age groups, with the highest among infants and those aged over 50 years.
Between 2016 and 2019, 3,689 deaths with influenza as the underlying or associated cause were reported in Australia, with 68 (1.8%) of these recorded in Aboriginal and/or Torres Strait Islander people. The majority of deaths were within the >50 years age group.
Comment
- Influenza is responsible for the largest number of notifications and hospitalisations of any vaccine preventable disease.
- In 2016–2019, compared to the previous reporting period, hospitalisation rates increased by 220% for Aboriginal and/or Torres Strait Islander people and by 250% for other Australians.
- It is very important for influenza vaccination to be promoted among all Aboriginal and/or Torres Strait Islander people aged 6 months and older.
