RSV, Flu or COVID-19? A Pediatrician Explains What Parents Should Know
Pediatrician Melissa Wallach, M.D., explains how to tell RSV, flu, COVID-19 and the common cold apart — and when to call your doctor.
By
Lana Pine
| Published on November 12, 2025
2 min read
This time of year, parents often face a familiar challenge: figuring out what’s behind their child’s runny nose, cough or fever. According to Melissa Wallach, M.D., pediatrician at K. Hovnanian Children’s Hospital at Hackensack Meridian Jersey Shore University Medical Center, RSV, flu, COVID-19 and the common cold can look strikingly similar — but there are some key differences that can help parents know when to worry and when to wait it out.
The common cold is generally mild. Children may have a stuffy nose, sneezing, sore throat and mild fever, but they usually still have energy to play and eat. In contrast, the flu tends to hit harder and faster — children may go from feeling fine in the morning to exhausted and achy by afternoon. Higher fevers (often up to 103 F), body aches, chills, headaches and fatigue are common, and younger kids may also experience vomiting or diarrhea.
RSV (respiratory syncytial virus) is particularly concerning in infants and young children because their smaller airways are more prone to inflammation. Signs like wheezing, rapid breathing or difficulty feeding can signal respiratory distress and may require hospitalization for oxygen or fluids. Fortunately, prevention options are improving — expectant mothers can now get vaccinated during pregnancy, and new monoclonal antibody treatments are available to protect infants from RSV.
COVID-19, while no longer as severe as during the height of the pandemic, still overlaps with other respiratory viruses. Symptoms can range from mild coldlike congestion to fever, fatigue and occasionally loss of taste or smell. Parents should stay alert to persistent or worsening symptoms and consult their pediatrician when in doubt.
Wallach stresses that fever alone isn’t always cause for panic — it’s the body’s natural response to infection. However, persistent high fevers (over 104 F), signs of dehydration (such as dry mouth, fewer wet diapers or no tears when crying), or trouble breathing should prompt a call to your doctor or a visit to urgent care. For reliable information, she recommends trusted sources like HealthyChildren.org, the Centers for Disease Control and Prevention and the American Academy of Pediatrics.
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