RSV in Newborns and Infants: What Parents Need to Know

What Is RSV?

Respiratory syncytial virus (RSV) is a common respiratory virus that causes mild, cold-like symptoms in older children and adults. But for newborns and young infants — especially those under 6 months of age — RSV can be serious, even life-threatening. It is the single leading cause of hospitalization in babies under one year old in the United States.

RSV spreads easily through droplets when an infected person coughs or sneezes, and through contact with contaminated surfaces. In fall and winter, RSV season overlaps with flu season — and a newborn's immune system simply isn't equipped to fight it the way older children can.

Why Newborns Are at Higher Risk

Newborns and young infants have narrow airways. When RSV causes inflammation and mucus buildup in those small passages, even minor swelling can make breathing significantly harder. Babies breathe primarily through their noses (they are obligate nose-breathers), so nasal congestion that an adult barely notices can be genuinely distressing for a newborn.

The babies at highest risk for serious RSV illness include:

Newborns under 6 months of age
Premature babies (born before 37 weeks gestation)
Babies with congenital heart disease or chronic lung conditions
Babies with weakened immune systems
Infants who were not breastfed (breast milk contains protective antibodies)

RSV Symptoms in Newborns and Infants

RSV usually starts like a common cold and progresses over the first few days. In newborns, early symptoms include:

Runny nose or nasal congestion
Low-grade fever (in older infants — any fever in a baby under 3 months is urgent)
Cough
Decreased appetite and difficulty feeding
Fussiness or unusual irritability

In more serious cases — particularly bronchiolitis (RSV infection of the small airways) — symptoms worsen to include:

Rapid breathing (more than 60 breaths per minute in an infant)
Wheezing or a whistling sound when breathing
Flaring of the nostrils with each breath
Grunting sounds, especially at the end of each breath
Visible "pulling in" of the skin between or below the ribs (retractions)
Blue or pale color around the lips, mouth, or fingernails (cyanosis)
Extreme fatigue or difficulty staying awake

When to Call Your Pediatrician — or Go to the ER

Call Hummingbird Pediatrics at (609) 808-3123 right away if your baby has:

Any fever at all in a baby under 3 months (100.4°F / 38°C or higher)
Signs of breathing difficulty — rapid breathing, retractions, flaring nostrils, or grunting
Feeding poorly or refusing more than one feeding in a row
Fewer wet diapers than usual (sign of dehydration)
Unusual sleepiness or difficulty waking

Go to the emergency room immediately if your baby has blue or pale coloring, stops breathing even briefly, or appears severely distressed.

How RSV Is Diagnosed and Treated

There is no specific antiviral treatment for RSV in otherwise healthy infants. Treatment focuses on supportive care — keeping your baby comfortable and making sure they can breathe and stay hydrated. At a sick visit, we will:

Check your baby's oxygen levels with a painless pulse oximeter
Assess breathing effort and lung sounds
Evaluate hydration and feeding intake
Use a nasal aspirator (or suction in-office) to clear nasal passages
Advise on home comfort measures
Refer to the emergency department if oxygen supplementation is needed

Hospitalization may be necessary for infants who cannot maintain adequate oxygen levels or are too exhausted from breathing effort to feed.

Home Care for Mild RSV

For infants with mild RSV symptoms who are breathing comfortably and feeding adequately, home care includes:

Nasal saline and gentle suctioning — Use saline drops and a bulb syringe or NoseFrida before feedings to clear the nose
Cool-mist humidifier — Place in the baby's room to help moisten airways (clean it daily)
Small, frequent feedings — Babies tire out faster when congested; smaller feedings more often help maintain hydration
Upright positioning — Hold your baby upright or at a slight incline when awake to ease breathing (never leave an infant inclined and unattended for sleep)
Avoid smoke exposure — Secondhand smoke worsens RSV symptoms significantly

Do not use over-the-counter cold or cough medicines in babies under 2 years — they are not effective and can be harmful. Ask us before using any medication.

Preventing RSV: What You Can Do

There is no widely available vaccine for RSV in healthy infants, but there are meaningful steps you can take to reduce your newborn's risk:

Handwashing — Insist that everyone who touches your baby washes their hands first
Limit visitors — Especially during RSV season (fall through early spring), minimize exposure to large groups
Keep sick people away — Ask friends and family members with cold symptoms to wait until they are well
Breastfeed if possible — Breast milk provides antibodies that help protect against respiratory infections
Avoid daycare exposure — If possible, delay group childcare for the first few months during RSV season
Nirsevimab (Beyfortus) — A monoclonal antibody injection (not a vaccine) is now recommended for most newborns born during or entering their first RSV season. Ask us at your prenatal visit or newborn checkup whether your baby qualifies

When to Schedule a Sick Visit

If your baby under 6 months has cold symptoms and you're unsure whether they're serious, call us. We have same-day and next-day sick visit slots for exactly these situations. You know your baby best — if something feels off, trust that instinct and call (609) 808-3123.

If you're expecting a baby, ask about RSV protection options at your free prenatal pediatrician visit — we can talk through the Beyfortus recommendation and what to watch for in the first weeks home.