RSV in Babies: What Families Need to Know

What RSV is and how it spreads

RSV stands for respiratory syncytial virus. It is the most common cause of bronchiolitis (inflammation of the small airways) and pneumonia in children younger than 1 year 1Ref 1Centers for Disease Control and Prevention (2024).Clinical Overview of RSV.RSV as leading cause of infant hospitalization and most common cause of bronchiolitis and pneumonia in children under 1 year; 2–3% of infants under 6 months hospitalized annually. The virus infects the respiratory tract — nose, throat, and lungs — and spreads through respiratory droplets and contact with contaminated surfaces. Almost all children have been infected with RSV at least once by age 2. RSV peaks in fall and winter.

The virus can live on surfaces for several hours and on hands for about 30 minutes, making household transmission very easy. Good handwashing and keeping young infants away from people who are sick with colds are the most practical ways to reduce exposure.

How RSV affects young babies differently

Young babies — especially those under 6 months old — have smaller, narrower airways. When RSV causes inflammation in the small tubes that lead to the lungs (bronchiolitis), even a small amount of swelling and mucus can make breathing significantly harder. Approximately 2–3% of infants under 6 months are hospitalized with RSV each year 1Ref 1Centers for Disease Control and Prevention (2024).Clinical Overview of RSV.RSV as leading cause of infant hospitalization and most common cause of bronchiolitis and pneumonia in children under 1 year; 2–3% of infants under 6 months hospitalized annually.

Babies at higher risk for more serious RSV illness include:

• Babies born prematurely (especially before 32 weeks)
• Newborns under 3 months old
• Babies with chronic lung conditions or congenital heart disease
• Babies who are immunocompromised

Signs of RSV in a baby

RSV typically starts like a cold:

• Runny nose (often clear at first, then thicker)
• Mild cough
• Low-grade fever
• Fussiness

In young babies, over the first few days the illness may progress to the lower airways, and breathing symptoms can develop or worsen 3Ref 3American Academy of Pediatrics Subcommittee on Diagnosis and Management of Bronchiolitis (2014).Clinical Practice Guideline: The Diagnosis, Management, and Prevention of Bronchiolitis.Supportive care as the recommended management for bronchiolitis; guideline against routine albuterol, systemic steroids, or antibiotics in otherwise healthy infants with bronchiolitis:

• Faster breathing than usual
• Wheezing — a whistling or musical sound on breathing out
• Retractions — the skin between or below the ribs, or just below the neck, pulls inward with each breath
• Grunting with each breath
• Flared nostrils
• Poor feeding — a baby working hard to breathe may not be able to suck and breathe at the same time

Care at home for mild RSV

Most RSV illness in babies is mild and managed at home with supportive care 3Ref 3American Academy of Pediatrics Subcommittee on Diagnosis and Management of Bronchiolitis (2014).Clinical Practice Guideline: The Diagnosis, Management, and Prevention of Bronchiolitis.Supportive care as the recommended management for bronchiolitis; guideline against routine albuterol, systemic steroids, or antibiotics in otherwise healthy infants with bronchiolitis:

• Saline nasal drops and gentle nasal suctioning before feeds can help clear congestion
• Small, frequent feeds — a baby who is struggling to breathe may feed better with shorter, more frequent sessions
• Monitor wet diapers — this is a practical way to tell if the baby is getting enough fluid
• Age-appropriate acetaminophen for fever (ibuprofen is not recommended under 6 months)
• Smoke-free environment

Antibiotics do not treat RSV — it is a virus. The AAP's bronchiolitis guideline does not recommend albuterol, systemic steroids, or routine chest X-rays for typical bronchiolitis in otherwise healthy babies 3Ref 3American Academy of Pediatrics Subcommittee on Diagnosis and Management of Bronchiolitis (2014).Clinical Practice Guideline: The Diagnosis, Management, and Prevention of Bronchiolitis.Supportive care as the recommended management for bronchiolitis; guideline against routine albuterol, systemic steroids, or antibiotics in otherwise healthy infants with bronchiolitis.

Prevention: a new option for families

A preventive monoclonal antibody, nirsevimab (brand name Beyfortus), is now CDC-recommended for most infants under 8 months entering their first RSV season 2Ref 2Centers for Disease Control and Prevention (2024).RSV Immunization Guidance for Infants and Young Children.CDC recommendation for nirsevimab for infants under 8 months entering first RSV season; at least 70% real-world effectiveness against hospitalization. It is not a vaccine but a protective antibody given as a single injection. Real-world data show nirsevimab reduces RSV-related hospitalization in infants by at least 70% 2Ref 2Centers for Disease Control and Prevention (2024).RSV Immunization Guidance for Infants and Young Children.CDC recommendation for nirsevimab for infants under 8 months entering first RSV season; at least 70% real-world effectiveness against hospitalization. A maternal RSV vaccine (Abrysvo) given during weeks 32–36 of pregnancy is an alternative approach for mothers who prefer to protect their baby before birth.

Good handwashing, keeping young babies away from people who are sick, and avoiding crowds during RSV season remain practical prevention strategies regardless of antibody status.

What the recovery timeline usually looks like

RSV illness typically lasts 1–2 weeks. The first 3–5 days tend to be the hardest, with breathing symptoms often peaking around days 3–4 before gradually improving. The cough can linger for 2–3 weeks after other symptoms have resolved. RSV infection does not provide lasting immunity, so reinfection in future seasons is possible, though later infections in healthy children are usually mild.