Winter is peak season for some communicable diseases like flu and respiratory syncytial virus (RSV).
Since the start of the year:
- almost 100,000 cases of flu have been reported – about 22,000 more than this time last year
- more than 61,000 cases of RSV have been reported – about 24,000 fewer than this time last year.
Many factors can affect case numbers. These higher numbers of flu cases could be the result of:
- more people getting tested for respiratory diseases following a summer wave of COVID-19
- seasonal changes – flu tend to spread more in winter because cold weather keeps people indoors, where viruses can pass more easily from person to person
- fewer people getting vaccinated.
It’s too soon to predict the severity of this year’s flu or RSV season. But we’re keeping a close eye on case numbers, hospitalisations and deaths – as we do for many other diseases.
Our surveillance activities
This figure shows the influenza cases notified to the National Notifiable Diseases Surveillance System from 2022 to 1 June 2025.
Flu is one of the nationally notifiable diseases – these are diseases that present a risk to public health.
Health authorities in each state and territory report cases to us daily through the National Notifiable Diseases Surveillance System.
We also track data through other surveillance systems, including:
- Influenza Complications Alert Network (FluCAN)
- FluTracking
- Australian Sentinel Practices Research Network (ASPREN)
- Short Period Incidence Study of Severe Acute Respiratory Infection (SPRINT-SARI).
This is part of our surveillance activities, which help us to:
- better understand and respond to disease patterns and national trends
- inform public health policy to reduce disease.
Our epidemiologists analyse the information, and we publish regular reports, including the Australian Respiratory Surveillance Reports.
The latest report, published today, shows that in the past fortnight, there was a:
- 64% increase in COVID-19 cases
- 65% increase in flu cases
- 28% increase in RSV cases
It also shows that:
- both the RSV and flu seasons are under way, with increasing case numbers following patterns seen in previous years
- influenza vaccine coverage for the 2025 seasonal campaign is lower than at the same time last year.
What you can do
You can take steps to protect yourself from infectious diseases – prevention depends on the disease and how it spreads.
For flu and RSV, the best ways to protect yourself are to:
- get vaccinated – see recommendations and eligibility for flu and RSV
- stay home if you are sick with cold and flu symptoms, and wear a mask if you need to leave home
- put physical distance between yourself and others
- wash your hands regularly
- cough and sneeze into your elbow or a tissue, and throw the tissue in the bin
- avoid touching your eyes, nose and mouth, particularly if you are around people who are unwell
- regularly clean objects and surfaces you use often, such as mobile phones and door handles.
If you’re unwell, healthdirect’s symptom checker can help you decide whether to see a healthcare professional and locate one near you.