How to Tell if You Have RSV, Flu, or COVID-19

It starts with a scratchy throat. Maybe a little congestion. Then the body aches set in, and before you know it, you’re down for the count. But what exactly are you dealing with? Is it just a stubborn cold, or something more serious like RSV, the flu, or COVID-19?

With overlapping symptoms, these respiratory illnesses can be difficult to distinguish. Each one has different risks, different timelines, and different ways of spreading. And when you’re sick, knowing what you have can make all the difference in how you recover—and how you protect those around you.

Understanding the Differences Between RSV, Flu, and COVID-19

RSV, influenza, and COVID-19 are all respiratory viruses, meaning they primarily affect the nose, throat, and lungs. While they share many similarities, they come from different viral families, which means they don’t always behave the same way in the body.

• RSV (Respiratory Syncytial Virus) is a common virus that can affect people of all ages, but it’s especially dangerous for infants, older adults, and those with weakened immune systems. While many cases are mild, RSV can lead to severe lung infections, particularly in young children.
• Influenza (Flu) is caused by influenza viruses and can result in a range of symptoms from mild to severe. It tends to come on suddenly and can cause fever, chills, muscle aches, and fatigue that lasts for days.
• COVID-19 is caused by the SARS-CoV-2 virus, which has continued to evolve since it first emerged. While some cases feel like a mild cold, others can cause severe breathing problems, long-lasting fatigue, and complications like pneumonia or blood clotting issues.

Although these illnesses share common symptoms, they don’t always follow the same course. Understanding the key differences can help you determine what you’re dealing with and when to seek medical care.

How Symptoms Overlap—and How They Don’t

While RSV, flu, and COVID-19 can all cause fever, cough, and fatigue, the way these symptoms appear can vary. Some come on gradually, while others hit like a truck.

Fever and Body Aches

A high fever is a telltale sign of the flu. It often spikes suddenly and is usually accompanied by chills and muscle aches that make it difficult to get out of bed. COVID-19 can also cause fever and body aches, but they tend to come on more gradually. RSV, on the other hand, causes fever primarily in infants and young children—adults with RSV may never develop a fever at all.

Cough and Congestion

Coughing is common across all three illnesses, but RSV often causes a distinct, wet, wheezy cough that lingers for weeks. Flu and COVID-19 tend to cause drier coughs, though COVID-19 is also associated with shortness of breath, especially in moderate to severe cases.

Congestion and a runny nose are more common in RSV than in flu or COVID-19. If your symptoms feel like a severe cold with lots of mucus, RSV could be the culprit—especially if a baby or older adult in your household develops symptoms, too.

Loss of Taste and Smell: The COVID-19 Giveaway

One of the biggest indicators of COVID-19 is a sudden loss of taste or smell. While the flu can sometimes cause a reduced sense of taste due to congestion, COVID-19 can cause a complete loss of these senses even without a stuffy nose.

Who’s Most at Risk for Severe Illness?

RSV: A Bigger Threat to Infants and Older Adults

For most healthy adults, RSV feels like a bad cold. But for young babies, RSV can be serious—sometimes leading to hospitalization due to breathing difficulties. Older adults with weakened immune systems or lung disease are also at higher risk.

Flu: A Sudden Onset with Severe Fatigue

The flu tends to hit hardest in young children, adults over 65, pregnant women, and those with underlying health conditions like asthma or heart disease. Complications can include pneumonia, worsening of chronic conditions, and, in some cases, severe dehydration.

COVID-19: Lingering Symptoms and Long-Term Effects

COVID-19 affects a broad range of people, but older adults and those with conditions like diabetes, obesity, or heart disease are at the highest risk for complications. Unlike RSV or flu, COVID-19 has also been linked to long-term symptoms, including fatigue, brain fog, and persistent shortness of breath—known as long COVID.

When to Seek Medical Care

Most cases of RSV, flu, and COVID-19 resolve on their own with rest, hydration, and over-the-counter symptom relief. However, there are times when medical attention is necessary.

Signs You Should See a Doctor Immediately

• Difficulty breathing, wheezing, or chest pain
• A fever that doesn’t improve with medication
• Severe dehydration (no urine output, dizziness, dry mouth)
• Confusion or extreme fatigue
• Blue lips or skin (especially in infants)

If you or a loved one experiences any of these symptoms, don’t wait—seek urgent care right away.

Testing: The Only Way to Be Sure

The only way to definitively determine whether you have RSV, flu, or COVID-19 is through testing. Because symptoms overlap, even experienced healthcare providers can’t always tell the difference just by looking at you.

At TGH Urgent Care powered by Fast Track, we offer on-site rapid testing for RSV, flu, and COVID-19, providing fast and accurate results so you can take the right steps to protect yourself and others.

How to Protect Yourself from RSV, Flu, and COVID-19

While there’s no way to completely eliminate the risk of getting sick, there are simple steps you can take to reduce your chances of infection.

1. Get Vaccinated

Flu shots and COVID-19 vaccines help protect against severe illness and reduce the spread of these viruses in the community. While there isn’t a widely available RSV vaccine for adults, some infants may qualify for preventive treatments.  Consult with your primary care physician about receiving vaccines.

2. Wash Your Hands Often

Regular handwashing with soap and water is one of the best ways to prevent the spread of respiratory viruses. If soap and water aren’t available, use hand sanitizer with at least 60% alcohol.

3. Stay Home When Sick

If you feel unwell, staying home helps prevent the spread of illness to others. This is especially important for protecting infants, the elderly, and those with compromised immune systems.

4. Cover Your Coughs and Sneezes

Coughing or sneezing into your elbow (rather than your hands) can help prevent virus particles from spreading through the air.

5. Keep Your Distance

Avoid close contact with people who are sick, and try to maintain space in crowded indoor areas during peak cold and flu season.

TGH Urgent Care powered by Fast Track Is Here to Help

When you’re sick, you need fast, reliable care—and that’s exactly what we provide at TGH Urgent Care powered by Fast Track. Whether you’re experiencing symptoms of RSV, flu, or COVID-19, we offer on-site testing, medical evaluations, and personalized treatment recommendations to help you recover quickly.

With 20 locations across the Greater Tampa Area, we make it easy to get the care you need, when you need it. Plus, with our Save My Spot e-Check-in, you can fill out your forms electronically for a faster check-in, minimizing wait times and getting you back on the road to recovery as soon as possible.

We’re open seven days a week, from 8 a.m. to 8 p.m., because we know that illnesses don’t wait for business hours. If you’re feeling unwell and need expert care, visit TGH Urgent Care powered by Fast Track today.