Cold, Flu, COVID, or RSV? What Parents Need to Know in 2026

With school back in session, cold and flu season is underway. With so many illnesses circulating, it can be difficult to know what your child has caught. Kids First Pediatrics can evaluate your child’s symptoms, provide a diagnosis, and recommend appropriate care. Keep reading to learn about the differences among the common cold, flu, COVID-19, and RSV.

Why Are These Illnesses Difficult to Tell Apart?

The common cold, flu, COVID-19, and RSV are all respiratory illnesses that can cause symptoms such as coughing, congestion, fatigue, and fever. Symptoms can vary by child, and it may not always be possible to identify the illness based on symptoms alone. Your child’s pediatrician may recommend testing when needed to confirm a diagnosis.

RSV

RSV can cause fever, coughing, fatigue, congestion, sneezing, decreased appetite, and difficulty breathing. Symptoms are often most severe between days three and five and may last one to two weeks.

Most children recover without complications. However, RSV can spread into the lower airways and cause bronchiolitis or pneumonia. According to the American Academy of Pediatrics, RSV is the most common cause of hospitalization among infants younger than one year, and approximately two to three out of every 100 infants with RSV may require hospital care. Because these symptoms overlap with other respiratory illnesses, testing is needed to confirm RSV. Learn more about RSV from HealthyChildren.org. 

Babies younger than six months, children born prematurely, and children with certain heart, lung, immune, or neuromuscular conditions have a higher risk of severe illness. Parents should closely monitor a child with RSV for changes in breathing, feeding, hydration, and alertness. Learn more about children at increased risk from the CDC.

Flu

Flu symptoms often include fever, chills, headache, body aches, fatigue, a dry cough, congestion, and a sore throat. Children may also experience vomiting or diarrhea. Symptoms typically begin one to four days after exposure. Because flu can resemble COVID-19, RSV, and other respiratory illnesses, testing is the only way to confirm that a child has influenza.

COVID-19

COVID-19 may cause fever, coughing, fatigue, muscle or body aches, congestion, difficulty breathing, sore throat, headache, sneezing, vomiting, or diarrhea. Some children may also experience a change in their sense of taste or smell. These symptoms can be difficult to distinguish from other respiratory illnesses, so testing is the only way to confirm COVID-19.

Common Cold

Cold symptoms are generally milder and may include coughing, congestion, sneezing, a sore throat, fatigue, a low-grade fever, or slightly swollen glands. Colds are upper respiratory infections caused by many different viruses. It is common for otherwise healthy children to experience several colds each year. There is no single test for the common cold. A pediatrician will usually diagnose it based on the child’s symptoms and examination after considering or testing for other illnesses when appropriate. Symptom information adapted from the American Academy of Pediatrics’ guide to RSV, flu, COVID-19, and the common cold.

What may help you tell them apart?

Cold: usually milder and centered on congestion, sneezing, and sore throat.

Flu: often begins suddenly and is more likely to cause fever, chills, body aches, headache, and significant fatigue.

RSV: may resemble a cold initially, but breathing trouble and poor feeding are especially important warning signs in babies and young children.

COVID-19: Symptoms vary widely and can closely resemble a cold, flu, or RSV. Testing is needed to confirm.

When Should You Seek Medical Care?

Call your child’s pediatrician right away if your child has:

• Fast breathing, wheezing, grunting, or flaring nostrils

• Skin pulling in around the ribs or lower neck while breathing

• Poor feeding or signs of dehydration, including fewer than one wet diaper every eight hours

• Significantly reduced activity or alertness

• A rectal temperature of 100.4°F or higher in a baby younger than three months

• Symptoms that worsen or do not begin improving after seven days

Call 911 immediately if your child:

• Has severe difficulty breathing

• Has pauses in breathing

• Has lips, skin, or nail beds that appear blue, purple, or gray

• Is unresponsive or cannot be awakened

These recommendations are based on guidance from the American Academy of Pediatrics on RSV warning signs and when to call emergency medical services.

If your child is experiencing respiratory symptoms or you are concerned about their health, schedule an appointment with Kids First Pediatrics for an evaluation and guidance on the appropriate next steps.

*This article is informational and is not a substitute for medical attention or information from your provider.