Common Respiratory Viruses: Colds, Flu, COVID-19 and RSV

Colds, flu, COVID-19 and RSV are the respiratory viruses most Australians will come across, especially in the cooler months. Most infections are mild and get better with rest and fluids, but some people are at higher risk of serious illness. Knowing the differences, staying up to date with vaccinations and recognising warning signs can help you look after yourself and your family.

What are respiratory viruses?

Respiratory viruses infect the nose, throat, airways and lungs. They spread through coughs, sneezes and tiny particles in the air, and from contaminated surfaces. In Australia, cases usually rise in autumn and winter, although COVID-19 and some others circulate all year.

The common respiratory viruses compared

Other viruses, such as adenovirus, parainfluenza (a common cause of croup in children) and human metapneumovirus, cause similar symptoms. Because the symptoms overlap so much, a test is the only reliable way to tell some of these viruses apart.

The common cold

Colds are the most frequent respiratory infection. According to healthdirect, symptoms usually get better on their own within 7 to 10 days, although a cough can linger. Antibiotics don’t help colds, because colds are caused by viruses. Rest, fluids, saline nasal sprays and simple pain relief can ease symptoms. Itchy eyes and sneezing in spring? Our hay fever guide explains how to tell allergies from a cold.

Influenza (flu)

Flu tends to come on suddenly and make you feel much sicker than a cold, often with high fever, aches and exhaustion that keep you in bed for several days. It can lead to complications such as pneumonia, and can be serious for higher-risk groups.

A yearly flu vaccine is recommended for everyone aged 6 months and over, ideally before flu season starts. It’s provided at no cost under the National Immunisation Program for some groups, including young children, pregnant women, older people, Aboriginal and Torres Strait Islander people and people with certain medical conditions. Your GP or pharmacist can tell you whether you’re eligible.

Antiviral treatment may be recommended for some people with flu, particularly those at higher risk. It works best when started within 48 hours of symptoms beginning, so don’t wait if you’re in a higher-risk group.

COVID-19

COVID-19 symptoms range from very mild to severe. Most people recover at home, but older people and those with certain health conditions are more likely to become seriously unwell. If you test positive and are at higher risk, speak to a doctor promptly. Antiviral treatment needs to be started within 5 days of symptoms beginning, and PBS eligibility criteria apply (for example, age and certain risk factors); your doctor will check whether you’re eligible. Our article on COVID-19 and PBS access to treatment explains more.

If symptoms last for weeks after infection, read Living with long COVID.

RSV

For most older children and adults, RSV feels like a cold. But it’s a leading cause of bronchiolitis and pneumonia in babies, and can also be serious for older adults and people with heart or lung disease.

Protection for babies has improved in recent years. According to healthdirect, pregnant women can have an RSV vaccine between 28 and 36 weeks of pregnancy, which passes protection to the baby for the first months of life. Babies whose mothers weren’t vaccinated, and some higher-risk babies, may be able to receive an RSV immunisation instead. Ask your GP, midwife or obstetrician what’s recommended for you and your baby.

What helps when you’re unwell

• Rest, and stay home from work, school or childcare until you feel better and any fever has gone.
• Drink plenty of fluids.
• Use simple pain and fever relief if needed. Your pharmacist can advise what suits you or your child.
• Saline nasal spray or drops can help with a blocked nose. Ask a pharmacist before using decongestants, especially for children.
• Honey can soothe a cough in children over 12 months and adults. Never give honey to babies under 12 months.
• If you have COVID-19 or flu symptoms, consider a rapid antigen test, and wear a mask around others and avoid visiting people at higher risk while you’re unwell.

Preventing respiratory infections

• Stay up to date with vaccinations, including flu, COVID-19 and RSV vaccines where recommended. The Department of Health has information on immunisation in Australia.
• Wash your hands with soap and water often, or use an alcohol-based hand rub.
• Cover coughs and sneezes with a tissue or your elbow, and put tissues straight in the bin.
• Stay home when you’re sick, and keep sick children home.
• Protect people at higher risk by avoiding visits to newborns, older relatives or people who are unwell while you have symptoms.

When to see a GP

See a doctor if:

• you’re in a higher-risk group and have flu or COVID-19 symptoms (early assessment matters because antiviral treatment is time-sensitive)
• symptoms aren’t improving after a week, or you start to improve and then get worse
• you have a high fever that isn’t settling
• you have a cough that lasts more than 3 weeks
• you have asthma or COPD and your symptoms are flaring
• you have ear pain, sinus pain or a severe sore throat (see our guide to tonsillitis)
• a baby or young child is feeding poorly or seems unwell

When to get urgent help

Call 000 or go to your nearest emergency department if you or someone you’re caring for:

• has difficulty breathing, is breathing very fast, or is struggling to speak
• has chest pain or pressure
• has blue or grey lips or skin
• is very drowsy, confused or hard to wake
• is a baby under 3 months with a fever of 38°C or higher
• is a baby who is grunting, sucking in at the ribs or throat when breathing, pausing in breathing, or not feeding

How Teldoc can help

Our AHPRA-registered GPs can assess cold, flu and COVID-19 symptoms by phone or video, 7 days a week from 9 am to 7 pm (Sydney time). Most patients are seen within 15 minutes. Your doctor can:

• check your symptoms and risk factors and look for warning signs
• discuss whether antiviral treatment is suitable and prescribe it if clinically appropriate, with an eScript sent to your phone
• arrange tests through our pathology and radiology referrals if needed
• provide a medical certificate for work, study or carer’s leave
• tell you if you need to be seen in person

General consultations are $55 on weekdays and $75 on weekends and public holidays. Babies under 12 months are bulk billed with a valid Medicare card. See our fees page, or read more about cold and flu consultations and COVID-19 consultations.

Frequently asked questions

How can I tell if I have a cold, flu or COVID-19?

Colds are usually milder, with a runny nose and sore throat. Flu often starts suddenly with fever, aches and exhaustion. COVID-19 symptoms overlap with both, so a test is the only reliable way to know. If you’re at higher risk, see a doctor early.

Do antibiotics help with respiratory viruses?

No. Antibiotics only work against bacteria. Colds, flu, COVID-19 and RSV are caused by viruses. A doctor may prescribe antibiotics if a bacterial infection develops, such as some cases of pneumonia.

When is the best time to get a flu vaccine?

Ideally before flu season, which is usually in autumn, so you’re protected when cases peak in winter. It’s still worth getting vaccinated later in the season if you missed out. A new vaccine is needed every year.

Is RSV dangerous for babies?

RSV can cause serious breathing problems in babies, particularly in the first months of life. An RSV vaccine in pregnancy or an immunisation for the baby can help protect them. Call 000 if a baby is struggling to breathe or not feeding.

This article is general health information and isn’t a substitute for advice from your own doctor. If you’re worried about your health, speak to a GP. In an emergency, call 000.

Medically reviewed by Dr Vafa Derakshan (MBBS, FRACGP), September 2026