Views in this article should not replace medical advice. If you have symptoms of a respiratory infection, please speak to and follow the advice of a healthcare professional.
Influenza is a viral infection that causes characteristic symptoms that can help you identify it early and seek medical advice.1 Influenza, is a short-lived, contagious, respiratory illness caused by a virus that can cause severe illness.1,2
Influenza can be easily confused with other respiratory illnesses, such as the common cold because some milder symptoms are similar.3 Recognising the symptoms of influenza early is key to effective treatment to prevent the virus spreading.3
In general, influenza is worse than the common cold, and symptoms are more intense. Also, colds generally do not result in serious health problems, such as pneumonia, bacterial infections or hospitalisations.1-3 Possible serious complications triggered by influenza include not only pneumonia, but can also include myocarditis, encephalitis and sepsis, all of which can increase the risk of death.4
Table adapted from reference 3.
x = rare, uncommon or slight; xx = fairly common or sometimes; xxx = usual or common
Warning signs of increased severity of influenza can include difficulty breathing or shortness of breath, persistent pain or dizziness, dehydration, as well as severe muscle pain and weakness.4
You can feel unwell even after the fever has resolved, and this can last for up to two weeks, meaning you may be unable to carry out your normal daily activities for some time.1,5
Many people think that there is little point in contacting their doctor when they have influenza. It has been shown that few people infected with influenza seek medical care within the first two days of developing symptoms.6 However, if you could be considered to be at high-risk of influenza, it is important to seek medical advice and testing (where available) as soon as you realise you have symptoms, in order to help to shorten the duration and impact of your illness.1,7,8
Tests that differentiate between the influenza virus and other respiratory viruses with similar symptoms, including COVID-19, are available from healthcare professionals.7,8
As with any airborne infectious disease, everyday preventive actions such as staying away from people who are sick, covering coughs and sneezes and frequent handwashing are always important.1,2
Before the onset of influenza, getting the influenza vaccine can reduce the odds of becoming infected.1 However, the effectiveness of the influenza vaccine depends on a number of different factors, including your age, general health, when you get the vaccine and how well matched it is to the dominant flu strains for the current season.9,10
It may be tempting to ask for an antibiotic to manage your viral influenza infection. However, antibiotics are not an appropriate treatment as they are designed to treat bacterial infections and have no effect on viral infections.11
You may choose to use over-the-counter (OTC) medication to manage the symptoms of influenza . While OTC medication can help with reducing your fever, aches, pains and congestion they do not directly affect the course of the influenza virus infection or reduce the ability to pass the infection on to others.12 If you are at risk for influenza-related complications, you should not use OTC medicines to delay seeking medical attention, but should immediately consult your doctor.7,8,12 People at high-risk for complications include those ≥65 years of age, those with certain chronic medical conditions (such as asthma, diabetes, heart disease or who have weakened immune systems ), pregnant women and children under five years of age.1,2
There are antiviral treatment options available that are specifically designed to treat influenza infections.8 Influenza antiviral drugs are not OTC medicines and you can only get them if you have a confirmed diagnosis of influenza via a prescription from a doctor.8
Influenza antivirals, which have been shown to shorten the duration of influenza symptoms, can also reduce the risk of severe illness and death, with the greatest benefit noted when antiviral treatment is administered as soon as possible after the onset of influenza symptoms.8
Shorten the course of influenza
Reduce complications of influenza
Decrease risk of influenza-related hospitalisations and mortality
Want to find out more about influenza?
WHO 2018. Influenza (Seasonal). [Internet; cited March 2023]. Available at:
Centers for Disease Control and Prevention. Key Facts about Influenza (Flu). [Internet; cited March 2023]. Available from:
Centers for Disease Control and Prevention. Cold Versus Flu. [Internet; cited March 2023]. Available from:
Centers for Disease Control and Prevention. Flu Symptoms and Complications. [Internet; cited March 2023]. Available from:
Centers for Disease Control and Prevention. Influenza. Stay Home When You Are Sick. [Internet; cited March 2023]. Available from:
Biggerstaff M, et al. J Infect Dis. 2014; 210: 535-44.
WHO. WHO policy brief: COVID-19 Testing. [Internet; cited March 2023]. Available from:
Centers for Disease Control and Prevention. Influenza Antiviral Medications: Summary for Clinicians. [Internet; cited March 2023]. Available from:
World Health Organization. Influenza Vaccines. [Internet; cited March 2023]. Available from:
Centers for Disease Control and Prevention. Vaccine Effectiveness: How Well Flu Vaccines Work. [Internet; cited March 2023]. Available from:
Centers for Disease Control and Prevention. Flu (Influenza). [Internet; cited March 2023]. Available from:
Klepser ME. Drugs. 2014;74:1467–79.
Ison M, et al. Lancet Infect Dis. 2020; 20(10): 1204-1214.
Updated May 2023
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