Flu vs. RSV vs. COVID: How to Tell the Difference

In the winter months, it can feel like everyone is sick and for good reason. Flu, RSV, and COVID often circulate at the same time, and they can cause many of the same symptoms. Because these illnesses overlap, it’s not always possible to tell what you have based on symptoms alone.

Table of Contents

This guide explains the most common signs of each illness, when testing is helpful, and when you should consider visiting urgent care.

Why So Many Viruses Circulate in Winter

Respiratory viruses spread more easily during colder months because people spend more time indoors, ventilation may be limited, and dry air can help viruses survive longer. This creates the perfect environment for infections to spread through households, schools, and workplaces.

Common Symptoms All Three Illnesses Share

Flu, RSV, and COVID can all cause:

• Fever or chills
• Cough
• Congestion or runny nose
• Fatigue
• Sore throat
• Headache
• Body aches

Because these symptoms are so similar, testing is often the best way to confirm what’s causing your illness.

Flu Symptoms: What It Usually Feels Like

The flu often comes on suddenly and can hit hard.

Common flu symptoms include:

• Sudden fever
• Chills
• Body aches
• Headache
• Significant fatigue
• Dry cough

The flu can cause complications such as pneumonia, especially for older adults, young children, pregnant people, and those with chronic conditions.

RSV Symptoms: Often Worse for Young Children and Older Adults

RSV (Respiratory Syncytial Virus) is especially common in babies and young children, but it can also be serious for older adults.

Common RSV symptoms include:

• Runny nose
• Cough
• Sneezing
• Fever
• Wheezing
• Decreased appetite (especially in children)

In infants, RSV may cause:

• Fast breathing
• Flaring nostrils
• Trouble feeding
• Irritability or low energy

COVID Symptoms: What Stands Out

COVID symptoms vary widely. Some people experience mild illness, while others develop more severe symptoms.

Common COVID symptoms include:

• Fever
• Cough
• Fatigue
• Sore throat
• Congestion
• Headache
• Body aches

Some people also experience:

• Loss of taste or smell
• Shortness of breath
• Stomach symptoms (nausea, vomiting, diarrhea)

How Long Do These Illnesses Last?

Illness duration can vary, but typical timelines include:

• Flu: often improves in 5–7 days, fatigue may linger longer
• RSV: mild cases may last 1–2 weeks
• COVID: symptoms may last about 1–2 weeks, but fatigue and cough can persist

If symptoms are worsening, lasting longer than expected, or affecting breathing, it’s important to be evaluated.

When Should You Get Tested?

Testing is especially helpful when:

• You need to know whether to isolate or return to school/work
• You’re at higher risk for complications
• You may be eligible for antiviral treatment
• You live with someone at high risk
• Symptoms are severe or worsening

Testing can also help your provider recommend the most appropriate next steps.

When to Visit Urgent Care for Respiratory Symptoms

Seek urgent care if you have:

• Shortness of breath
• Chest pain
• Wheezing
• Persistent high fever
• Severe sore throat or dehydration
• Symptoms that worsen after improving
• Concern for a child with fast breathing or trouble feeding

How AFC Supports You

AFC Urgent Care can evaluate respiratory symptoms and provide testing when needed. If you’re sick, our team can help you understand what’s causing your symptoms and whether treatment or follow-up care is necessary.

What to Remember About Flu, RSV, and COVID

In winter, flu, RSV, and COVID can look very similar and you don’t always need to guess. Testing and evaluation can help you make safer decisions for yourself and others, especially if you’re at higher risk or your symptoms are more severe.

Visit AFC Urgent Care for testing and respiratory symptom evaluation. Walk-ins welcome, or schedule an appointment online.