RSV in Babies: Symptoms, Treatment & When to Seek Care

What Is RSV and Why Is It Dangerous for Babies?

RSV (respiratory syncytial virus) is a common respiratory virus that causes cold-like symptoms in most people but can lead to serious lower respiratory tract infections in infants, particularly those under 6 months old, premature babies, and children with underlying health conditions.

Respiratory syncytial virus, commonly known as RSV, is one of the most prevalent respiratory viruses affecting infants and young children worldwide. The virus belongs to the Paramyxoviridae family and spreads easily through respiratory droplets when an infected person coughs or sneezes, or through direct contact with contaminated surfaces. RSV is so widespread that nearly every child will have been infected at least once by their second birthday, and many children experience multiple infections throughout childhood.

While RSV causes only mild cold symptoms in most older children and adults, it poses a significant threat to infants, particularly those in their first six months of life. The virus can travel from the upper respiratory tract (nose and throat) into the lower respiratory tract (bronchioles and lungs), causing conditions known as bronchiolitis and viral pneumonia. These lower respiratory infections can make breathing extremely difficult for small babies whose airways are already very narrow.

The danger of RSV in babies relates primarily to the anatomy and physiology of infant airways. Babies have much smaller airways than older children and adults, so even small amounts of swelling and mucus can significantly obstruct breathing. Additionally, young infants have immature immune systems that cannot fight the virus as effectively, and premature babies may lack adequate antibodies that would normally be passed from mother to baby during the last weeks of pregnancy.

How RSV Spreads

RSV is highly contagious and spreads through several routes. The virus can survive on hard surfaces like doorknobs, toys, and countertops for several hours, making it easy to pick up through everyday activities. Direct contact with respiratory secretions from an infected person, either through coughing, sneezing, or touching, is the primary mode of transmission. The virus can also spread when someone touches a contaminated surface and then touches their face, particularly their eyes, nose, or mouth.

The incubation period for RSV is typically 4-6 days, meaning symptoms appear within about a week of exposure. People with RSV are usually contagious for 3-8 days, though infants and people with weakened immune systems may continue to spread the virus for up to 4 weeks. This extended contagious period in young children contributes to the rapid spread of RSV in daycare settings and among family members.

RSV Seasonality

RSV follows a predictable seasonal pattern in temperate climates, with cases typically beginning to rise in fall and peaking during winter months. In most regions, RSV season runs from November through March, though the exact timing can vary by geographic location and year. Understanding this seasonality helps parents and healthcare providers prepare for periods of increased risk and implement preventive measures during peak transmission times.

What Are the Symptoms of RSV in Babies?

RSV symptoms in babies typically begin with runny nose and congestion, followed by cough and sometimes fever. Warning signs of severe illness include rapid or labored breathing, wheezing, difficulty feeding, and unusual tiredness. Symptoms are usually worst on days 3-5 of the illness.

RSV infection in babies typically progresses through distinct phases, and recognizing the pattern helps parents understand what to expect and when to become concerned. The illness usually starts with upper respiratory symptoms that resemble a common cold, but in some babies, particularly those in high-risk groups, the infection can progress to affect the lower respiratory tract, causing more serious breathing problems.

During the first 2-3 days of illness, babies with RSV typically show cold-like symptoms including a runny nose, sneezing, and mild cough. They may have a low-grade fever (100-101°F or 37.8-38.3°C) and seem slightly fussier than usual. Many babies also experience decreased appetite because nasal congestion makes it difficult to breathe while feeding. These early symptoms can be difficult to distinguish from other viral upper respiratory infections.

The illness typically peaks around days 3-5, which is when parents should watch most carefully for signs of worsening. If the virus moves into the lower respiratory tract, babies may develop bronchiolitis, characterized by inflammation and mucus production in the small airways of the lungs. This causes the classic wheezing sound and can significantly affect breathing. The cough often becomes more pronounced and may sound wet or productive.

Common Symptoms of RSV in Infants

• Runny nose and nasal congestion: Often the first symptom to appear, making feeding difficult
• Cough: May start dry and become wet-sounding as the illness progresses
• Fever: Usually mild (100-101°F), though some babies have no fever
• Decreased appetite: Babies may refuse feeds or take only small amounts
• Irritability: Babies often become fussier than usual
• Sneezing: Common in the early stages of infection
• Wheezing: A whistling sound when breathing out, indicating lower airway involvement

Warning Signs Requiring Immediate Medical Attention

While most RSV infections resolve on their own with supportive care, some babies develop severe illness requiring immediate medical intervention. Parents should learn to recognize the warning signs that indicate a baby is struggling to breathe or becoming dangerously ill. These signs often develop gradually, so monitoring your baby closely throughout the illness is essential.

Symptoms in Premature Babies

Premature babies may present differently than full-term infants and are at significantly higher risk for severe RSV disease. In preterm infants, apnea (pauses in breathing) may be the first and most prominent symptom, sometimes appearing before other signs of respiratory infection. These breathing pauses can be life-threatening and require immediate medical attention. Premature babies may also deteriorate more rapidly than full-term infants, making close monitoring essential.

Which Babies Are at Highest Risk for Severe RSV?

Babies at highest risk for severe RSV include premature infants (born before 35 weeks), infants under 6 months old, babies with congenital heart disease or chronic lung disease, and children with weakened immune systems. These groups are more likely to require hospitalization.

While RSV can affect any baby, certain groups of infants are at significantly higher risk for developing severe illness that may require hospitalization. Understanding these risk factors helps parents and healthcare providers identify babies who need extra vigilance during RSV season and may benefit from preventive measures such as the monoclonal antibody palivizumab.

Age is one of the most important risk factors for severe RSV disease. Infants under 6 months of age are at the highest risk because their immune systems are still developing and their airways are very small. Within this age group, babies under 3 months are at even greater risk and require particularly close monitoring. The protective antibodies that mothers pass to their babies during pregnancy begin to wane after birth, leaving young infants increasingly vulnerable as these antibodies decline.

Premature birth significantly increases RSV risk for several reasons. Babies born before 35 weeks gestation miss out on the full transfer of maternal antibodies that occurs primarily in the last weeks of pregnancy. Additionally, their lungs are less mature and their airways are even smaller than those of full-term infants. Premature babies who required oxygen therapy or mechanical ventilation after birth are at particularly high risk due to underlying lung damage.

High-Risk Groups for Severe RSV

• Premature babies: Especially those born before 35 weeks gestation
• Infants under 6 months: Highest risk age group for all babies
• Congenital heart disease: Babies born with heart defects
• Chronic lung disease: Including bronchopulmonary dysplasia from prematurity
• Weakened immune systems: Due to illness or medical treatment
• Neuromuscular disorders: Conditions that affect breathing muscles
• Down syndrome: Associated with increased RSV severity

How Is RSV Treated in Babies?

RSV treatment is primarily supportive care including fluids, nasal suctioning, and monitoring. There is no specific antiviral medication for RSV. Most babies recover at home with careful attention to hydration and breathing. Severe cases may require hospitalization for oxygen therapy or IV fluids.

Because RSV is a viral infection, antibiotics are not effective and should not be used unless a secondary bacterial infection develops. Currently, there is no approved antiviral medication that can shorten or cure RSV infection in otherwise healthy infants. Treatment focuses on supportive care to keep babies comfortable and safe while their immune systems fight off the virus, which typically takes 1-2 weeks.

For most healthy, full-term babies with mild RSV symptoms, home care is appropriate and effective. The goals of home treatment are to maintain hydration, keep the airways as clear as possible, and monitor for any signs of worsening. Parents play a crucial role in providing this supportive care and watching for warning signs that indicate the baby needs medical attention.

Hospitalization becomes necessary when babies cannot maintain adequate oxygen levels, are unable to feed sufficiently, or show signs of severe respiratory distress. In the hospital, babies may receive supplemental oxygen through a nasal cannula or face mask, IV fluids to prevent dehydration, and close monitoring of vital signs. In severe cases, some babies require higher levels of respiratory support including high-flow nasal cannula, CPAP (continuous positive airway pressure), or rarely, mechanical ventilation.

Home Care for Babies with RSV

Providing good supportive care at home can help your baby recover more comfortably and may prevent the need for hospitalization. The following strategies are recommended by pediatricians for managing mild to moderate RSV symptoms at home:

• Keep your baby hydrated: Offer frequent, smaller feeds rather than larger, less frequent ones. Breastfed babies should nurse more often. Formula-fed babies may need smaller, more frequent bottles. Older infants who eat solids should continue to receive breast milk or formula as their primary nutrition.
• Clear nasal congestion: Use saline drops (2-3 drops in each nostril) followed by gentle suctioning with a bulb syringe or nasal aspirator. Do this before feeds and before sleep to help your baby breathe and eat more easily. Avoid over-suctioning, which can cause swelling.
• Use a cool-mist humidifier: Adding moisture to the air can help loosen mucus and soothe irritated airways. Clean the humidifier daily to prevent mold and bacteria growth.
• Keep your baby's head elevated: Slight elevation can help with drainage and make breathing easier. Never use pillows or soft bedding - instead, you can place a folded towel under the crib mattress to create a gentle incline.
• Manage fever if present: If your baby has a fever and seems uncomfortable, you can use infant acetaminophen (for babies 2 months and older) or ibuprofen (for babies 6 months and older). Always follow dosing instructions based on weight, not age.
• Monitor closely: Watch for changes in breathing pattern, color, feeding, and alertness. Count breaths per minute (normal is under 60 for infants) and look for signs of labored breathing.

Hospital Treatment

When babies require hospitalization for RSV, the medical team provides supportive care that cannot be safely given at home. The most common reasons for admission are low oxygen levels (hypoxia) and dehydration from inability to feed. Hospital treatment may include:

• Supplemental oxygen: Delivered through a nasal cannula or face mask to maintain safe oxygen levels
• IV fluids: To prevent and treat dehydration when babies cannot take enough by mouth
• Nasogastric tube feeding: If babies are too tired to feed but do not require IV fluids
• Continuous monitoring: Heart rate, breathing rate, and oxygen levels are watched constantly
• Deep suctioning: Medical staff can suction more effectively than can be done at home
• Advanced respiratory support: Including high-flow nasal cannula or CPAP for more severe cases

Most babies hospitalized for RSV stay for 2-5 days and make a full recovery. The length of stay depends on how quickly oxygen levels and feeding improve. After discharge, babies may continue to have a cough for several weeks as the airways heal.

How Can I Prevent My Baby from Getting RSV?

Prevent RSV by washing hands frequently, avoiding contact with sick people, keeping babies away from crowds during RSV season, cleaning surfaces regularly, and not allowing smoking around your baby. For high-risk infants, preventive antibody treatment (palivizumab or nirsevimab) may be recommended.

While it is impossible to completely eliminate the risk of RSV infection, several evidence-based strategies can significantly reduce your baby's chances of getting sick or developing severe illness. These preventive measures are particularly important during RSV season (typically November through March) and for babies in high-risk groups.

Hand hygiene is the single most effective way to prevent the spread of RSV and other respiratory viruses. The virus can survive on hands for 30 minutes or more, making hand-to-face transmission common. Parents, caregivers, and anyone who handles the baby should wash hands thoroughly with soap and water for at least 20 seconds before touching the baby, especially before feeding. If soap and water are not available, alcohol-based hand sanitizers can be used as an alternative.

Limiting exposure to potential sources of infection is another key prevention strategy. During RSV season, try to keep your baby away from crowded indoor spaces such as shopping malls, busy restaurants, and indoor play areas. Ask family members and friends to stay away if they have cold symptoms, even if they seem mild. Remember that adults and older children often carry RSV with only minor symptoms but can easily transmit it to vulnerable infants.

Prevention Strategies for All Babies

• Frequent hand washing: Everyone who touches the baby should wash hands first
• Avoid sick contacts: Keep people with cold symptoms away from your baby
• Limit crowds: Especially during RSV season (November-March)
• Clean surfaces: Regularly disinfect frequently touched surfaces and toys
• No smoking: Never allow anyone to smoke around your baby - smoke exposure increases RSV risk
• Breastfeeding: Continue breastfeeding if possible, as it provides protective antibodies
• Keep siblings home: If older children are sick, try to limit their contact with the baby

Prevention for High-Risk Babies

For babies at high risk of severe RSV disease, additional preventive measures may be recommended by healthcare providers. The monoclonal antibody palivizumab (Synagis) has been available for many years and is given as a monthly injection during RSV season to help prevent severe RSV infection. More recently, nirsevimab (Beyfortus) was approved as a single-dose option that provides protection throughout the RSV season.

These preventive antibody treatments are typically recommended for premature infants, babies with chronic lung disease from prematurity, infants with significant congenital heart disease, and children with severely weakened immune systems. Your baby's healthcare provider can determine if preventive treatment is appropriate based on your baby's specific risk factors and current guidelines from the American Academy of Pediatrics.

How Long Does RSV Last and What Is the Recovery Timeline?

RSV infection typically lasts 1-2 weeks, with symptoms being worst around days 3-5. Most babies recover fully, though a cough may persist for up to 4 weeks. Premature babies and those with underlying conditions may take longer to recover.

Understanding the typical timeline of RSV illness helps parents know what to expect and when improvement should occur. While every baby is different, most RSV infections follow a predictable course. The initial upper respiratory symptoms (runny nose, mild cough) typically appear 4-6 days after exposure and last for several days before either resolving or progressing to lower respiratory involvement.

If bronchiolitis develops, symptoms generally peak around days 3-5 of the illness. This is when babies are at highest risk for developing breathing difficulties and when hospitalization, if needed, is most likely to occur. Parents should be most vigilant during this critical window. After the peak, symptoms gradually improve over the following 5-7 days, though the timeline can be longer for premature babies or those with underlying health conditions.

The cough associated with RSV is often the last symptom to resolve and may persist for 2-4 weeks after other symptoms have improved. This lingering cough does not necessarily indicate ongoing infection but rather reflects the time needed for irritated airways to fully heal. Parents should not expect the cough to disappear immediately and should understand that gradual improvement is normal.

What to Expect During Recovery

• Days 1-3: Cold-like symptoms develop - runny nose, mild cough, possible low fever
• Days 3-5: Peak of illness - watch closely for breathing difficulties, wheezing
• Days 5-10: Gradual improvement in breathing, appetite returns
• Weeks 2-4: Cough may persist but should be improving; baby returns to normal activity

When Should I Take My Baby to the Doctor for RSV?

Contact your doctor if your baby has a worsening cough, is feeding poorly, has a fever over 100.4°F (38°C) if under 3 months, or seems more tired than usual. Seek emergency care immediately for difficulty breathing, blue lips, or pauses in breathing.

Knowing when to seek medical care is one of the most important things parents can learn about RSV. While most RSV infections can be safely managed at home, some babies need medical evaluation and treatment. The key is to monitor your baby closely and trust your instincts - if something seems wrong, it is always better to seek evaluation than to wait.

A good first step is to call your baby's healthcare provider for guidance. Many doctors' offices have nurses who can help assess symptoms over the phone and advise whether your baby needs to be seen. If your baby's provider is unavailable and you are concerned, urgent care or emergency room evaluation is appropriate.

Contact Your Doctor If Your Baby:

• Has cold symptoms that are getting worse rather than better
• Has a fever of 100.4°F (38°C) or higher, especially if under 3 months old
• Is feeding less than half of normal or refusing to feed
• Has fewer wet diapers than usual (less than 4 in 24 hours)
• Seems unusually tired, irritable, or difficult to console
• Has a cough that is worsening or preventing sleep
• Is breathing faster than normal or making wheezing sounds