Different stages of flu

Influenza is a highly infectious respiratory illness. It’s spread through droplets in the air when an infected person talks, coughs, or sneezes.

Last year, over 500,000 Australians had the flu.¹ Understanding the different stages of the flu can help you manage the illness most effectively.

“The typical duration of flu is 5 to 7 days,” says Professor at NICM Health Research Institute and School of Science, Kamal Dua. “In severe cases, or for people who have pre-existing conditions, it may last longer. For many people, the fatigue and cough from the flu can last for another 1 or 2 weeks.”

Incubation

This is when the virus enters the body and begins to replicate. It usually occurs 1 to 4 days post-exposure.

“The virus is in your body. You might feel a bit tired or under the weather, but you might not be experiencing any significant symptoms yet,” says senior researcher at NICM Health Research Institute and School of Science, Dr Keshav Raj Paudel.

Early phase

“You might experience sudden fevers, aches and fatigue, as well as headaches, muscle or joint pain, dry cough, sore throat and a runny or blocked nose” says Kamal. “You’re highly contagious at this stage.”

What to do: “It’s important to rest and hydrate. If you are in a high-risk category, consider taking antivirals within 48 hours of symptoms showing. These need to be prescribed by your doctor. You should also avoid being in close contact with other people to avoid passing the illness on.”

Peak illness

“This is when most people experience the most severe symptoms,” says Keshav. “Fevers may start to peak, and respiratory symptoms such as a sore throat, cough and congestion can become more pronounced. You are still contagious.”

What to do: “Manage symptoms with paracetamol or ibuprofen. Continue to rest and stay hydrated.”

Recovery stage

“While symptoms begin to improve, fatigue may linger,” says Kamal. “You can be infectious up to 24 hours after your last fever.”

What to do: If you’re stopping fevers by using paracetamol or ibuprofen then you’re likely to still be infectious, so even if you’re feeling better, you should still avoid shared spaces or use a mask.

Post-Recovery stage

The virus has gone from your body, but you are still recovering. You might still be experiencing a cough or fatigue.

What to do: “Start a gradual return to normal activity, but listen to your body and don’t overdo it,” says Keshav. “Ensure you are sleeping enough and eating a healthy, balanced diet to help restore energy.”

“The flu vaccine is the best protection against seasonal flu,” says Kamal. While it doesn’t prevent you from getting the flu, it can reduce the likelihood of severe symptoms.

It’s recommended that everyone aged 6 months or older receive an influenza vaccine. It's safe at all stages of pregnancy. The flu vaccine is free for people at high risk.

This year, a new needle-free vaccine is available for children aged 2 to 17, in order to help reduce stress or fear around needles.

“Anti-viral medication doesn’t kill the virus but reduces its spread in the body by inhibiting viral replication,” says Kamal. “It can help reduce the severity and duration of the virus and reduce any complications.”

“Most anti-virals are only effective if taken within 48 hours of the onset of any symptoms.”

High-risk groups who catch the flu are advised to take anti-viral medication. This includes older Australians, pregnant people, those who are immunocompromised, or have chronic diseases such as lung or heart disease, or diabetes.²

Healthdirect provides free health advice and information, including a cold or flu symptom checker. Visit their website or call them on 1800 022 222

The Australian Government Department of Health and Aged Care provides advice on influenza vaccination and who is eligible for free vaccines.