RSV (Respiratory Syncytial Virus)

Definition: A common respiratory virus that infects the lungs and airways. In older children and adults, RSV usually causes mild cold-like symptoms. In babies, premature infants, and young children, it can cause serious breathing problems and is a leading cause of hospitalization for infants under 1 year old.

Parent Tip: RSV often starts looking like a regular cold: runny nose, cough, mild fever. What makes RSV different in young children is how it can settle into the lower airways and cause real trouble breathing 3 to 5 days into the illness. Watch for the signs that breathing has become work: fast breathing, nostrils flaring, skin pulling in between the ribs with each breath, or a wheezing sound on the exhale. Babies may also have trouble feeding because they are too short of breath to suck and swallow at the same time.

When to Call 911

• Lips, tongue, or face turning bluish or gray
• Severe trouble breathing or pauses in breathing
• Extreme drowsiness or difficulty waking the baby
• Severe dehydration: no wet diapers for 8 hours, no tears when crying, sunken soft spot

When to Call the Doctor

• Working hard to breathe (fast breathing, retractions, nostril flaring)
• Wheezing or persistent coughing fits
• Refusing to eat or drink, or taking only small amounts
• Fewer wet diapers than normal
• Fever in a baby under 3 months old
• Symptoms getting worse instead of better after a few days

Why It Matters: Almost every child gets RSV by age 2. For most kids it passes like any other cold, but for babies under 6 months, premature infants, and children with heart or lung conditions, it can be dangerous. There is now a preventive monoclonal antibody (nirsevimab) available for infants going into their first RSV season, and a vaccine for pregnant women in late pregnancy. Talk to your pediatrician about whether these options make sense for your family. Hand washing, avoiding sick contacts, and keeping older siblings from kissing the baby on the face all help reduce spread.

Related Terms: Airway, Breathing Trouble, Bronchiolitis, Colds, Dehydration, Fever, Pediatric Vital Signs, Pneumonia, Trouble Breathing

Written and reviewed by Jeremy Manke, Firefighter / Paramedic (22 years of emergency service)

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