Viral Co-Infections: Can You Really Have COVID-19, Flu and RSV at the Same Time?
, by Tatianna Gerard, 17 min reading time
When sniffles turn serious, and your rapid test shows negative for COVID-19, you might wonder — what else could it be? Or could it be more than one thing?
Respiratory virus season often brings with it a surge in COVID-19, influenza, and RSV (respiratory syncytial virus) infections. And as concerning as it sounds, it is possible to be infected with more than one of these viruses at the same time — a phenomenon known as viral co-infection.
While COVID-19 has become a familiar part of life, we now know that it can overlap with other respiratory infections, sometimes compounding symptoms and prolonging recovery. Hospitals and clinics are reporting more cases of dual or even triple infections, especially in vulnerable populations like older adults, immunocompromised individuals, and young children.
In this article, we break down what a co-infection really means, how to recognise the signs, what the latest science says, and how to protect yourself this season.
What is a viral co-infection?
A viral co-infection occurs when a person is infected with two or more viruses at the same time. In the context of respiratory illnesses, this might mean testing positive for COVID-19 and influenza, flu and RSV (respiratory syncytial virus), or — in rare cases — all three simultaneously.
These co-infections aren't just theoretical. In clinical settings, doctors have observed patients who present with symptoms of one illness, only to discover they are fighting multiple infections at once. This is particularly concerning during peak virus seasons, such as winter in Australia, when COVID-19, influenza, and RSV tend to circulate together.
Why do co-infections happen?
Co-infections can occur because different viruses target different cells or areas of the respiratory tract and use different mechanisms to replicate. Your immune system may be fighting one infection when another virus enters and takes hold — especially if your body is already run down or immunocompromised.
It’s also important to remember:
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Viruses don’t “cancel each other out” — having one doesn’t protect you from catching another.
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Children, older adults, people with chronic illnesses (like asthma, COPD, or heart disease), and those with weakened immune systems are more susceptible to co-infections.
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Close living conditions, such as aged care homes, shared housing, or households with young children, can increase the risk of spreading multiple viruses simultaneously.
What makes co-infections riskier?
When you’re fighting two or more viral infections, the severity of symptoms can intensify, recovery may take longer, and there may be a higher risk of complications such as:
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Worsening respiratory symptoms (e.g. increased breathlessness, wheezing, or persistent coughing)
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Hospitalisation, especially among vulnerable groups
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Delayed recovery, where symptoms linger longer than usual
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Increased chance of secondary bacterial infections like pneumonia
While healthy adults might recover without major issues, co-infections can seriously affect those who are already at risk — which is why early recognition and appropriate care are essential.
Are co-infections new?
Not exactly. Co-infections have always existed in the world of respiratory illnesses. However, the COVID-19 pandemic introduced a new and widespread virus into the mix. Now that COVID-19 is endemic and continues to mutate into new variants, the overlap between it, the flu, and RSV has become a growing concern for public health authorities — especially during winter when all three viruses are at peak.
Can you really get COVID-19, the flu, and RSV at the same time?
Yes — it is medically possible to contract COVID-19, influenza, and RSV at the same time. This type of triple viral co-infection, while rare, has been reported in clinical studies and case reports around the world. It can happen when all three viruses are circulating in the community — such as during winter respiratory season — and when a person’s immune system is exposed to more than one virus in close succession.
How likely is a triple infection?
Triple infections aren't common, but they're not unheard of — especially among:
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Children (whose immune systems are still developing)
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Older adults
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People with chronic illnesses or respiratory conditions (like COPD or asthma)
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Individuals who are immunocompromised
Each of these viruses — SARS-CoV-2 (COVID-19), Influenza (flu), and Respiratory Syncytial Virus (RSV) — can infect a person through the respiratory tract, but they use different receptors and mechanisms. That means being infected with one virus doesn’t block infection from another.
What are the symptoms of a co-infection?
When you’re infected with more than one respiratory virus — such as COVID-19, flu, and RSV — the symptoms often overlap and can be more severe or prolonged than when you have a single infection.
While each virus has its own unique characteristics, they all target the respiratory system. This means the signs of a viral co-infection can look very similar to one another and are often hard to tell apart without testing.
Common symptoms of co-infection
Many of the following symptoms are shared across COVID-19, influenza, and RSV:
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Fever or chills
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Cough (may be dry or productive)
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Sore throat
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Runny or congested nose
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Body aches and fatigue
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Shortness of breath or wheezing
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Headache
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Loss of taste or smell (more common in COVID-19)
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Sneezing
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Nausea or diarrhoea (sometimes seen in COVID-19 and flu)
What makes co-infection different?
In cases of co-infection, symptoms may:
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Start suddenly and become worse faster
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Last longer than a typical single-virus infection
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Fluctuate, with a person feeling slightly better before worsening again
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Cause increased inflammation and immune response, especially in vulnerable individuals
Because your immune system is fighting off more than one virus at once, you may feel more fatigued, experience heavier congestion, or have worsening respiratory symptoms such as wheezing or difficulty breathing.
In young children and older adults, RSV can cause more serious symptoms such as:
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Laboured breathing
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Grunting or flaring nostrils in babies
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Bluish lips or fingertips from low oxygen levels
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Decreased appetite or difficulty feeding
When should you seek medical attention?
If you’re experiencing persistent or severe symptoms, or you’re in a higher-risk category, it’s important to get assessed by a healthcare provider. Watch for red flags such as:
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Difficulty breathing
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Persistent high fever
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Chest pain or tightness
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Confusion or unusual drowsiness
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Worsening symptoms after initial improvement
Co-infections can increase the risk of hospitalisation and complications, especially in those with chronic conditions like asthma, COPD, diabetes, or heart disease.
How can you tell which virus you have?
With COVID-19, flu, and RSV sharing many symptoms — like fever, cough, and fatigue — it can be nearly impossible to know which one you have based on symptoms alone. This is especially true if you’ve got more than one virus at the same time, as the symptoms can overlap, intensify, or behave differently than expected.
Why symptoms alone aren’t enough
Even doctors can’t always tell just by looking or listening. For example:
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A sore throat, body aches, and fatigue? Could be flu… or COVID-19.
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Wheezing and shortness of breath? Common in RSV, but also occurs in COVID and asthma flare-ups.
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Loss of smell or taste? Used to be a strong indicator of COVID, but is less common with newer variants.
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Mild symptoms in a child? Could still be RSV, which may progress quickly.
This is why diagnostic testing is essential if you want to know what you’re dealing with — especially if you're in a high-risk group or need to protect vulnerable people around you.
What kinds of tests are available?
Here are the main ways to confirm which virus (or combination of viruses) is causing your symptoms:
1. Rapid Antigen Tests (RATs)
These are widely used for detecting COVID-19, offering quick results in just 15–30 minutes. However, standard RATs are designed specifically for COVID-19 and may not detect other viruses like flu or RSV unless they are part of a combination test.
Today, you can find combo rapid tests that detect multiple respiratory viruses in a single swab — including the Sonictec and HA Tech combo RATs, which test for COVID-19, Influenza A/B, and RSV. These are especially helpful when symptoms overlap or when it’s unclear which virus you may have.
There are also next-generation RAT kits now available that screen for five respiratory pathogens at once, including COVID-19, Influenza A, Influenza B, RSV, and Adenovirus (AdV). These expanded panels are ideal during peak respiratory virus season when multiple infections are circulating at once.
2. PCR Tests
A more sensitive lab test that can detect COVID-19, influenza A/B, and RSV from a single swab. These are often used in hospitals or clinics, especially for those with moderate to severe illness or underlying health conditions.
While at-home RATs are convenient and useful for early detection and isolation, it’s still important to consult a doctor if your symptoms worsen, you experience severe fatigue or breathing issues, or if you fall into a high-risk group. A healthcare provider may recommend confirmatory PCR testing or other treatments based on your condition.
What should you do if you suspect a co-infection?
1. Test early — and consider combo tests
Start by using a rapid antigen test (RAT). If you’re unsure which virus you might have or your symptoms are more severe than usual, consider using a combo test that checks for COVID-19, flu, and RSV in one go. These tests are especially helpful when symptoms overlap.
Early detection can help you:
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Begin isolation (if necessary)
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Get appropriate treatment sooner
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Reduce the risk of spreading the infection
🛈 Combo RATs like the ones from Sonictec and HA Tech can be done at home and are useful tools during the early stages of illness.
2. Monitor your symptoms closely
Keep track of your temperature, breathing, energy levels, and how your symptoms evolve. While most people recover at home with rest and fluids, some symptoms may indicate complications, especially in children, older adults, or people with chronic conditions.
Seek immediate medical attention if you experience:
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Shortness of breath
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Chest pain or tightness
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Confusion or difficulty waking up
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Bluish lips or face
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Dehydration or inability to keep fluids down
3. Avoid spreading it to others
Even if you’re unsure which virus you have, it’s wise to stay home, wear a mask, and practice good hygiene until symptoms improve. This is especially important if you live with or care for someone at higher risk of complications.
Shop face masks at Aussie Pharma Direct.
4. Speak to a doctor if you’re in a high-risk group
If you’re pregnant, immunocompromised, elderly, or have underlying conditions like COPD, asthma, or diabetes, check in with your doctor. They may want to assess whether antiviral treatments are appropriate — particularly in the case of flu or COVID-19, where early treatment can make a difference.
5. Use supportive care tools
To help ease symptoms at home, consider:
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Hydration and rest
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Pain relievers or fever reducers (if appropriate)
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Humidifiers or nasal sprays for congestion
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Products like Boost Oxygen for short-term oxygen support (note: not a replacement for medical oxygen therapy)
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A pulse oximeter to monitor blood oxygen levels, particularly if you have a respiratory condition
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Use an AirPhysio device — this Australian-made respiratory therapy tool helps loosen mucus and improve airflow using gentle resistance, making it ideal for people managing breathing issues due to viral infections like COVID-19, flu or RSV.
Can you prevent co-infection?
Get vaccinated
One of the most effective ways to prevent co-infection is through vaccination. Staying up to date on the recommended vaccines can significantly reduce your risk of severe illness and hospitalisation — especially when multiple viruses are circulating.
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COVID-19 (including booster doses): Protects against serious outcomes from current strains and helps reduce transmission in the community.
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Influenza (flu): An annual flu shot is recommended for most people, especially vulnerable groups such as children, the elderly, and people with chronic conditions.
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RSV: A newer addition to Australia's vaccine schedule, RSV vaccines are currently available for some high-risk adults and infants (availability varies).
Use respiratory protection
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Wearing a P2/N95 mask in crowded indoor areas, especially during peak virus seasons, lowers your risk of inhaling airborne particles from people who are infected. Masks are especially helpful if you’re immunocompromised or caring for someone vulnerable.
Practise good hygiene
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Wash hands regularly with soap and water, or use alcohol-based hand sanitiser (alternatively a natural hand sanitiser if you have sensitive skin) if soap isn’t available.
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Avoid touching your face, especially your eyes, nose and mouth.
Stay home when sick
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If you have any respiratory symptoms (even mild ones), stay home and rest — this protects others and prevents potential spread.
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Encourage others around you to do the same.
Keep your environment clean
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Disinfect commonly touched surfaces (like doorknobs, remotes, light switches).
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Use antimicrobial sprays or wipes in shared spaces.
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Consider using air purifiers or mould-prevention solutions, especially if someone in the household is high-risk.
Strengthen your immune system
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Get enough sleep, eat a nutritious diet, and manage stress.
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Consider supplements (like vitamin C, D, or zinc) if advised by your healthcare provider.
Conclusion
While catching a single virus is already unpleasant, co-infections involving COVID-19, influenza, and RSV are becoming increasingly relevant — especially during colder months when multiple respiratory viruses circulate at once. These co-infections can lead to more severe symptoms, a longer recovery time, and a higher risk of complications, particularly in older adults, young children, and those with underlying health conditions.
If you're unsure about your symptoms, get tested early and consult your healthcare provider. And remember, staying prepared doesn't just protect you — it helps protect your loved ones and the wider community too.