Published on May 15, 2023
Authored by Pfizer Medical Team
As we head into the Winter season, you may have developed a scratchy throat, runny nose or cough. Yes, it’s important to be aware that these symptoms could be due to COVID-19 – and a rapid antigen test will confirm this for you. However, other viral infections can also cause similar symptoms. Here, we provide a 101 of common causes of viral illness that you should be aware of.
You may have already noticed that viruses tend to spread with more ease during cooler weather. This phenomenon occurs because people tend to spend more time indoors together during winter (with the windows closed for added warmth). In this type of environment, germs are able to circulate from one person to another through the air or via close contact.1 Whether it is the ‘common cold’, the flu, norovirus, or COVID-19, we have created a symptom checker to help you to identify which virus could be ailing you. Read on to learn more, and remember to always call your local doctor for specific medical advice.
The ‘common cold’ is a term used to describe a respiratory illness infection which could actually be caused by a range of different types of viruses. Although 20-30% of colds are caused by unidentified bugs, rhinoviruses are known to cause up to 40% of all colds.2 Although these germs frequently circulate during winter and spring, a person may develop a cold at any time of the year.3
Cold symptoms can be similar to flu symptoms, but they are generally milder. Symptoms include the following:1
The flu is caused by the influenza virus. There are many different influenza strains – and these can change each year.5 The flu can be mild or severe - and can cause complications, such as bronchitis (inflammation of the airways of the lungs), pneumonia (infection of the lungs), ear infections, and in severe cases, death.5 Certain groups of people, including babies, pregnant women, older adults and people with underlying health conditions may be at risk of serious complications.5
An annual flu vaccine can help prevent you from becoming unwell with the flu.6 Annual flu vaccinations are recommended for all people aged 6 months and older. According to the Australian Immunisation Handbook, influenza vaccination is particularly recommended for children aged 6 months to <5 years; adults 65 years and older, Aboriginal and Torres Strait Islander people; people with medical conditions that increase their risk of influenza; homeless people, pregnant women, healthcare workers and carers; residents, staff and volunteers to aged care and long-term residential facilities; people working in essential community services; and commercial poultry and pork industry workers.6
COVID-19 is an illness caused by the coronavirus, SARS-CoV-2.8 Similar to the flu, COVID-19 symptoms can range from mild to severe.8 Older adults and people with underlying health conditions (such as diabetes, cardiovascular disease and chronic illness) may be at greater risk of developing serious complications, which may progress to the need for hospitalisation. In some cases, severe COVID-19 may lead to death.9
The following list includes a number of potential symptoms, but not all possible symptoms, of COVID-19. If you think you might have COVID-19, it is important that you get tested as soon as possible – either with a PCR test or rapid antigen test – so that you can protect yourself and others.10 If you do test positive, it is important to speak to your doctor as soon as possible - as you may be eligible for oral (at-home) COVID-19 treatment.11
COVID-19 symptoms may include:12
People with mild illness usually recover within 7 days. Some people take longer to recover.13 If you are concerned at any time about your symptoms, it is important to speak to your doctor.
COVID-19 can lead to serious complications, and even death. Call for urgent medical help if you experience the following symptoms:12
Norovirus refers to a group of viruses that cause acute gastroenteritis (often called stomach flu or gastro bug). Norovirus can spread through contaminated foods and water, or via contact with an infected person.14
If you think you may have the stomach flu or gastro bug, it could be norovirus. Common symptoms include:14
Other symptoms may include fever, headache and body aches. People with norovirus illness may experience diarrhoea or vomiting multiple times each day. This can increase the chances of developing dehydration. Symptoms of dehydration include dizziness, dry mouth and lack of urination.15
Symptoms can develop 12 to 48 hours after being exposed to norovirus. Generally, people with norovirus illness recover in 1 to 3 days.15
You should call a doctor if you experience any of the following:16
• Bloody stool
• Severe vomiting
• Stomach pain
• Dehydration
• Diarrhea that continues after several days
Frequent handwashing and social distancing to help stop the spread of infectious disease. These messages are important for our health generally. To minimise your risk of catching a viral illness:17
Wash your hands frequently
Disinfect common surfaces regularly (including countertops, doorknobs, remote controls, keyboards and light switches)
Use the crook of your elbow or tissue when sneezing
Wear a mask if you are close to other people (such as when using public transport, shopping, or at gatherings)
Where a vaccine is available and recommended, please talk to your local doctor about getting vaccinated to help protect you and your loved ones from these preventable illnesses.
External Resources
PP-PAX-AUS-0493 05/23