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Influenza
What is it?
Influenza is a virus that causes acute respiratory disease, and usually occurs between April to September each year1.
Symptoms of influenza include fever, cough, headache, muscle aches and pains, and a sore throat. While influenza can be a mild disease for some, it can cause severe illness in otherwise healthy people and can lead to hospitalisation. Most symptoms resolve within 2-7 days, although the cough may last for longer1.
People may be unwell and infectious before symptoms appear, with the incubation period of influenza being 1-4 days2.
How is it transmitted?
Influenza viruses are most commonly spread through the inhalation of viral particles of infected people and through direct contact with contaminated surfaces2.
At risk groups?
People at an increased risk of severe influenza include those who are: immunocompromised, transplant recipients, obese, have cardiac and chronic respiratory disease, and those with other chronic illnesses. Older adults, children under the age of 5, pregnant women, and Aboriginal, Torres Strait Islander, Māori and Pacific peoples are also at an increased risk.
Occupational groups are also considered to be at increased risk of influenza, due to an increased exposure in their workplace. These groups include healthcare workers, aged care and long-term residential facility workers and essential service providers.
Prevention?
Immunisation and practicing prevention strategies are the best way to protect against influenza infection1. The influenza vaccination is updated each year to include protection against circulating viruses, and is recommended every year for everyone aged 6 months or older3, and should be given from mid-April onwards, before the influenza season begins.
Prevention strategies to minimise the spread of influenza include, hand washing, cough etiquette, keeping high touch surfaces clean, and staying home when unwell. The use of additional infection prevention measures in healthcare settings include increased cleaning of high touch surfaces, personal protective equipment (PPE) and droplet and contact transmission-based precautions.
Key messages:
- Annual vaccination is the most important measure to prevent influenza and is recommended for anyone aged 6 months of age.
- Vaccination is free through the National Immunisation Program for high-risk groups.
- Occupational groups are at an increased risk and should be vaccinated annually.
References
- Better Health Channel. Influenza (flu). The Victorian Government. Updated 2 April 2024. Accessed 17 April, 2024. https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/flu-influenza
- Victorian Department of Health. Influenza. Victorian Department of Health. Updated 5 December 2023. Accessed 17 April, 2024. https://www.health.vic.gov.au/infectious-diseases/influenza
- Australian Technical Advisory Group on Immunisation (ATAGI). The Australian Immunisation Handbook. Australian Government Department of Health and Aged Care; 2022.