Flu vs. COVID-19 vs. RSV: How to Tell Which Respiratory Illness You May Have

When you develop a cough, fever, congestion, sore throat, or overwhelming fatigue, it can be difficult to know what is actually making you sick. Flu, COVID-19, and respiratory syncytial virus (RSV) are different respiratory infections, but many of their symptoms can look remarkably similar. Without testing or a medical evaluation, it may not be possible to determine which illness is responsible based on symptoms alone.

At UNI Urgent Care, we regularly evaluate patients with respiratory symptoms, including fever, coughs, colds, sore throats, and other common illnesses. Our services include rapid flu testing, rapid RSV testing, and COVID-19 testing, giving our healthcare team useful information when a respiratory infection needs to be evaluated.

Understanding the differences between flu vs. COVID-19 vs. RSV can help you recognize when testing or medical care may be appropriate.

 

Why Flu, COVID-19, and RSV Can Be Difficult to Tell Apart

Influenza, COVID-19, and RSV are caused by different viruses, but they can all affect the respiratory system. Symptoms can range from mild to significant, and the same person may experience a different combination of symptoms from one illness to another.

Common symptoms may include:

• Fever or chills

• Cough

• Runny or stuffy nose

• Sore throat

• Fatigue

• Headache

• Body aches

• Decreased appetite

• Breathing difficulties in more serious cases

Because these symptoms overlap, having a fever does not automatically mean you have the flu, and having congestion does not necessarily mean you have RSV. COVID-19 can also resemble either infection.

That is why we encourage patients not to rely solely on symptom lists when determining which respiratory illness they may have. A medical evaluation and appropriate testing can provide more useful information.

For additional information about how these respiratory illnesses can overlap, see Cleveland Clinic’s overview of RSV, flu, and COVID-19.

 

Flu vs. COVID-19 Symptoms

Flu and COVID-19 can be particularly difficult to distinguish.

Influenza commonly causes fever, chills, cough, sore throat, fatigue, headache, and muscle or body aches. Symptoms can appear suddenly, and some people feel significantly ill within a short period.

COVID-19 can also cause fever, cough, fatigue, sore throat, congestion, headaches, and body aches. Some people experience changes in taste or smell, although these symptoms are not present in every case. COVID-19 symptoms can also vary considerably from person to person.

One important point is that symptom severity does not reliably identify the virus. A mild illness can still be COVID-19, while influenza can range from mild to severe.

If you are experiencing respiratory symptoms, our team can consider your symptoms, how long you have been sick, your health history, and whether testing may be appropriate.

 

Flu vs. RSV Symptoms

Flu and RSV also share many symptoms.

RSV frequently causes congestion, runny nose, coughing, fever, and decreased appetite. Wheezing or breathing difficulties can occur, particularly when the infection affects the lower respiratory tract.

Flu may be more associated with sudden fever, pronounced body aches, chills, headache, and significant fatigue, although these symptoms are not exclusive to influenza.

RSV is often discussed in connection with infants and young children, but adults can develop RSV as well. Older adults and people with certain underlying health conditions may also be at greater risk of serious respiratory illness.

At UNI Urgent Care, our centers serve patients of all ages, and our current services include rapid RSV testing and rapid flu testing.

For additional information about RSV symptoms and when to seek medical attention, see Mayo Clinic’s RSV symptoms and causes resource.

 

COVID-19 vs. RSV Symptoms

COVID-19 and RSV can both cause cough, congestion, fatigue, fever, and sore throat. This overlap can make it especially difficult to identify the infection without testing.

RSV may cause significant congestion, coughing, wheezing, or difficulty breathing. COVID-19 may cause a wider variety of symptoms, including respiratory symptoms as well as fatigue, headaches, muscle aches, and other systemic symptoms.

However, there is no reliable symptom checklist that can always separate RSV from COVID-19.

For that reason, when symptoms are persistent, worsening, or concerning, an evaluation can help determine what testing or treatment may be appropriate.

 

Why Symptoms Alone May Not Identify the Infection

It is natural to search online for “flu vs COVID symptoms” or “RSV vs flu” when you become sick. Symptom information can be useful, but it has limitations.

For example, two people may both have fever, cough, congestion, and fatigue while having completely different infections. Another person may have only mild symptoms despite having one of the same viruses.

There is also the possibility of having more than one infection. Respiratory viruses can circulate at the same time, and co-infections can occur.

Instead of trying to diagnose yourself based solely on symptoms, consider how severe the illness is, how long symptoms have lasted, whether they are getting worse, and whether you have risk factors that could make respiratory infections more serious.

 

When Should You Consider Respiratory Testing?

Testing may be appropriate when knowing the cause of your symptoms could affect your care, help explain a worsening illness, or provide useful information for protecting people around you.

At UNI Urgent Care, our respiratory testing services include rapid flu testing, rapid RSV testing, and COVID-19 testing.

Testing can be particularly worth discussing when:

• Symptoms are significant or worsening

• You have a fever with respiratory symptoms

• You have persistent coughing

• You are experiencing unusual fatigue or body aches

• You have been exposed to someone with a respiratory infection

• You are at increased risk for complications

• You need clarification before returning to work, school, or normal activities

• Your symptoms do not seem to be improving as expected

Our healthcare team can review your symptoms and determine which testing options may be appropriate for your situation.

 

Flu Testing vs. COVID-19 Testing vs. RSV Testing

The purpose of respiratory testing is to help identify the infection responsible for symptoms.

Rapid flu testing can help evaluate whether influenza may be contributing to fever, cough, body aches, fatigue, or other symptoms.

COVID-19 testing can help determine whether SARS-CoV-2 is responsible for respiratory symptoms. UNI’s FAQ currently confirms that COVID-19 testing, including rapid testing, is available at our locations.

Rapid RSV testing can help evaluate RSV when symptoms such as congestion, coughing, fever, or wheezing are present.

Testing does not replace a medical evaluation. Results need to be considered alongside symptoms, timing, medical history, examination findings, and overall health.

 

Why Early Evaluation Can Matter

For some patients, getting evaluated sooner rather than later can be important.

Certain people are more vulnerable to complications from respiratory infections, including young children, older adults, pregnant individuals, people with chronic medical conditions, and people with weakened immune systems.

Early evaluation may also be useful when symptoms are worsening rather than improving.

At UNI Urgent Care, our goal is to provide convenient care for non-life-threatening illnesses without requiring patients to wait for a traditional appointment. Our centers offer walk-in care, and our website lists respiratory concerns such as flu, coughs and colds, fever, COVID-19, and RSV among the conditions we address.

 

When Respiratory Symptoms Require Urgent Care

Not every cough or fever requires an urgent care visit. Mild respiratory symptoms may often be monitored at home with rest, fluids, and appropriate symptom care.

However, an urgent care evaluation may be appropriate when symptoms are persistent, worsening, unusually severe, or causing concern.

Consider seeking medical evaluation if you experience:

• A persistent or worsening fever

• Significant coughing

• Wheezing

• Increasing congestion accompanied by other concerning symptoms

• Significant fatigue or weakness

• Difficulty staying hydrated

• Symptoms that improve and then become worse

• Breathing symptoms that concern you

• A respiratory illness that is especially concerning because of an underlying health condition

Our team can evaluate your condition and determine whether testing, treatment, monitoring, or additional medical care may be appropriate.

 

Emergency Warning Signs: When to Seek Immediate Medical Attention

Urgent care is designed for non-life-threatening conditions. Certain symptoms require emergency medical attention instead.

Seek immediate emergency care for serious warning signs such as:

• Severe difficulty breathing

• Severe or persistent chest pain or pressure

• Bluish, gray, or unusually pale lips or skin

• New confusion or inability to stay awake

• Severe weakness or sudden deterioration

• Signs of a serious lack of oxygen

• Any other symptom that appears life-threatening

When a medical emergency is occurring, call 911 or go to the nearest emergency department rather than waiting for an urgent care evaluation.

 

How UNI Urgent Care Can Help With Respiratory Illnesses

When you are unsure whether you have the flu, COVID-19, RSV, or another respiratory illness, getting the right evaluation can provide more clarity than trying to diagnose the illness yourself.

Our team at UNI Urgent Care evaluates patients with a wide range of non-life-threatening illnesses. Our current services include COVID-19 testing, rapid flu testing, rapid RSV testing, care for coughs and colds, fever, sore throats, asthma, and other common medical concerns. We also have on-site laboratory and X-ray services at our urgent care centers.

Depending on your symptoms and medical history, an evaluation may include a review of when your symptoms started, a physical examination, vital signs, and appropriate testing.

Our goal is to make the process convenient while helping patients understand what may be causing their symptoms and what steps to take next.

 

Frequently Asked Questions

Can you tell whether you have the flu, COVID-19, or RSV based on symptoms?

Not reliably. Flu, COVID-19, and RSV share many symptoms, including cough, fever, congestion, sore throat, and fatigue. Testing may be necessary to help identify the infection.

Is RSV only a concern for babies?

No. RSV can affect people of all ages. Infants and young children can be particularly vulnerable, but older adults and people with certain medical conditions may also experience more serious illness.

Does a fever mean I have the flu?

No. Fever can occur with influenza, COVID-19, RSV, and other infections. A fever alone cannot identify which virus is responsible.

Can you have flu and RSV at the same time?

Yes. Co-infections with respiratory viruses can occur. When symptoms are unusually severe or worsening, medical evaluation can help determine whether testing is appropriate.

Does UNI Urgent Care offer flu, COVID-19, and RSV testing?

Yes. Our current services include rapid flu testing, rapid RSV testing, and COVID-19 testing, including rapid COVID-19 testing.

When should I go to urgent care for respiratory symptoms?

Consider urgent care when symptoms are persistent, worsening, or concerning but do not appear to be a life-threatening emergency. Our team can evaluate symptoms and determine whether respiratory testing or additional care is appropriate.

 

Conclusion

Flu, COVID-19, and RSV can look remarkably similar, which is why determining the cause of a respiratory illness based solely on symptoms can be difficult. Fever, cough, congestion, sore throat, fatigue, and body aches can occur with more than one infection.

Instead of assuming that a particular symptom means you have the flu, COVID-19, or RSV, consider the complete picture. Pay attention to how quickly symptoms developed, whether they are improving or worsening, how severe they are, and whether you have health factors that increase your risk of complications.

When testing is appropriate, our services can help evaluate common respiratory infections. UNI Urgent Care offers rapid flu and RSV testing along with COVID-19 testing at our locations, providing convenient access to evaluation for many non-life-threatening respiratory concerns.

If you are dealing with persistent cough, fever, congestion, fatigue, sore throat, or other respiratory symptoms and are unsure what is causing them, our team is here to help. Walk-in urgent care is available for many non-life-threatening illnesses, and our respiratory testing services can help provide additional information when appropriate.

UNI Urgent Care
📍 Corporate Office: 826 Washington Road, Suite 110A, Westminster, MD 21157
📞 Phone: (410) 751-7480
🌐 Website: uniurgentcare.com

For severe or life-threatening symptoms, seek emergency medical attention immediately.