Respiratory syncytial virus (RSV) infects virtually every child by age 2, and it doesn’t stop there. Adults get reinfected throughout their lives, usually experiencing nothing worse than a common cold. But for infants, older adults, and people with compromised immune systems, the symptoms of RSV can escalate quickly from mild congestion to serious respiratory distress. According to the Centers for Disease Control and Prevention, RSV causes tens of thousands of hospitalizations among children under 5 each year and an estimated 100,000 to 160,000 or more hospitalizations among adults 65 and older annually in the United States, though the exact figures vary by season and surveillance method. Knowing which symptoms signal trouble can help you act before the situation becomes an emergency. For more on medical conditions, see our medical conditions guide.
TL;DR: RSV is usually a routine cold in healthy older children and adults, but it can cause severe lower-airway disease in infants, adults 65 and older, and people with chronic heart or lung disease or weakened immune systems. The most important skill is recognizing respiratory distress early. If breathing is fast or labored, the skin pulls in around the ribs, the lips or skin look bluish, breathing pauses, or a baby stops feeding and has far fewer wet diapers, treat it as an emergency. Prevention now includes infant antibodies, a maternal vaccine in pregnancy, and adult RSV vaccines. This article is educational and is not a substitute for care from your own clinician.
When to seek emergency care: Call 911 or go to the nearest emergency room immediately if a person of any age shows signs of respiratory distress. In an infant, these include struggling or working hard to breathe, visible rib or chest retractions (skin pulling in with each breath), flaring nostrils, grunting, a bluish tint to the lips, mouth, or fingernails (cyanosis), breathing very fast (more than about 60 breaths per minute), pauses or gaps in breathing (apnea), unusual lethargy or difficulty waking, or refusing to eat or drink with significantly fewer wet diapers than normal. In children and adults, seek emergency care for severe shortness of breath, bluish lips or skin, confusion, chest pain, or a high fever with worsening breathing. RSV can deteriorate rapidly in infants under 6 months old and in high-risk adults, so when in doubt, get evaluated.
What Is RSV?
RSV is a common respiratory virus that causes infections of the lungs and breathing passages. In most healthy older children and adults, it produces symptoms indistinguishable from a typical cold. The virus spreads through respiratory droplets when an infected person coughs or sneezes, through direct contact (kissing an infected child’s face), and by touching contaminated surfaces and then touching the eyes, nose, or mouth.
RSV season in the United States typically runs from fall through spring, with peak activity between December and February in most regions, though the timing shifted during and after the COVID-19 pandemic and can still vary year to year. Seasonal patterns are more variable in the southern U.S. and in tropical areas such as parts of Florida. The virus has an incubation period of about 4 to 6 days, and infected individuals are usually contagious for 3 to 8 days, though immunocompromised patients and young infants may remain contagious for up to 4 weeks.
Unlike some respiratory viruses, RSV does not produce lasting immunity. Reinfection occurs throughout life, though subsequent infections tend to be milder. The National Institutes of Health reports that RSV is the most common cause of bronchiolitis (inflammation of the small airways) and pneumonia in children under 1 year old in the United States.
RSV Symptoms in Infants (Under 12 Months)
Infants are the highest-risk group for severe RSV disease because their airways are small and their immune systems are immature. The symptoms of RSV in infants may look different from what you’d expect with a typical cold, and they can worsen rapidly over 2 to 3 days.
Early symptoms in infants include irritability and fussiness, decreased appetite or refusal to feed, runny nose, sneezing, and a mild cough. These initial symptoms are easily mistaken for a common cold, which is why parents need to watch for progression. In the youngest infants, sometimes the only early sign of RSV is irritability, reduced activity, or breathing difficulty, without an obvious cough or fever.
Warning signs that RSV is becoming serious in an infant:
- Rapid or labored breathing: Breathing faster than about 60 breaths per minute, flaring nostrils, or grunting with each breath
- Chest retractions: The skin between or below the ribs visibly pulls inward with each breath, indicating the baby is working hard to breathe
- Wheezing: A high-pitched whistling sound during breathing out
- Poor feeding: Difficulty sucking, swallowing, or breathing during feeds; eating less than half of normal amounts
- Dehydration signs: Significantly fewer wet diapers (for example, fewer than one wet diaper every 8 hours), no tears when crying, sunken fontanelle (soft spot)
- Cyanosis: Bluish color around the lips, mouth, or fingernails
- Apnea: Pauses in breathing lasting more than about 10 seconds, especially common in premature infants and very young babies
Premature infants (born before about 35 weeks), babies under 6 months old, infants with congenital heart disease, children with chronic lung disease, and babies with weakened immune systems are at the highest risk for severe RSV. According to the American Academy of Pediatrics, RSV is a leading cause of infant hospitalization and is responsible for an estimated 100 to 300 infant deaths annually in the U.S., with the highest burden in the first months of life.
RSV Symptoms in Children (Ages 1 to 5)
In toddlers and young children, RSV typically presents as a moderate cold that can progress to lower respiratory involvement. Symptoms include runny nose and congestion (often the first and most prominent symptom), cough that may worsen over several days, mild fever (roughly 100.4 to 102 degrees F), decreased appetite, and general irritability.
Most children in this age group recover within 1 to 2 weeks without complications. However, some develop bronchiolitis or pneumonia, especially if they have asthma or other underlying respiratory conditions. Signs that a toddler or young child needs medical attention include wheezing or difficulty breathing, a persistent high fever above about 104 degrees F, worsening symptoms after initial improvement (which may indicate a secondary bacterial infection), dehydration from poor drinking, and extreme lethargy or listlessness.
Children who develop wheezing with RSV may be at higher risk for developing recurrent wheezing or asthma later in childhood, though the relationship between RSV bronchiolitis and future asthma is complex and still being studied, according to ongoing pediatric research summarized by the NIH and in journals such as the New England Journal of Medicine.
RSV Symptoms in Adults
Healthy adults typically experience RSV as a routine upper respiratory infection. Symptoms include nasal congestion and runny nose, dry cough, mild headache, low-grade fever, sore throat, fatigue, and general malaise. Most healthy adults recover in 1 to 2 weeks and may not even realize they have RSV rather than a common cold or flu.
However, RSV poses a significantly greater risk for certain adult populations. Adults 65 and older, particularly those in nursing homes or long-term care facilities, can develop severe lower respiratory tract disease including pneumonia. Adults with chronic heart or lung disease (COPD, asthma, congestive heart failure) and immunocompromised adults (organ transplant recipients, those on chemotherapy, people with advanced HIV) are also at elevated risk. RSV can also worsen underlying conditions, triggering COPD flare-ups or heart failure exacerbations.
Warning signs of severe RSV in adults include significant shortness of breath, high or persistent fever, wheezing, rapid breathing, worsening cough with colored sputum, confusion or new disorientation (especially in older adults), and difficulty with daily activities due to respiratory symptoms. According to the CDC, RSV causes thousands of deaths each year among adults 65 and older in the United States, with estimates commonly cited in the range of 6,000 to 10,000 or more depending on the season.
RSV vs Flu vs COVID: How to Tell the Difference
RSV, influenza, and COVID-19 share many symptoms, making clinical differentiation difficult without testing. However, some patterns can help guide your thinking.
RSV in adults tends to produce more prominent nasal congestion and a gradual onset, with less severe body aches than the flu. Influenza typically hits suddenly with high fever, severe body aches, and intense fatigue. COVID-19 may include loss of taste or smell (less common with newer variants) and can cause a wider range of systemic symptoms.
In infants, RSV is distinguished by the prominence of wheezing and lower respiratory involvement (bronchiolitis), which is less common with flu and COVID in very young children. Ultimately, multiplex respiratory panels (tests that check for multiple viruses simultaneously) are the most reliable way to determine which virus is causing symptoms. These tests are widely available at hospitals, urgent care centers, and some pediatric offices, and telehealth clinicians can help you decide whether testing is worthwhile. For remote evaluation options, see our telehealth guide.
Treatment and Home Care
There is no specific antiviral medication for RSV in most patients. Treatment focuses on managing symptoms and preventing complications. For mild cases at home, supportive care includes adequate hydration, saline nasal drops and gentle suctioning for infants with congestion, cool-mist humidifiers, and rest. Fever and discomfort can be managed with acetaminophen or, in children over 6 months, ibuprofen; always follow the dosing on the product label or your clinician’s instructions, and never give aspirin to children or teenagers because of the risk of Reye syndrome.
For severe cases requiring hospitalization, treatment may include supplemental oxygen, intravenous fluids, nasal suctioning, and in critical cases, high-flow oxygen or mechanical ventilation. Ribavirin, an antiviral medication, is occasionally considered for severely immunocompromised patients but is not routinely recommended.
Antibiotics do not treat RSV because it’s a virus. However, if a secondary bacterial infection develops (such as bacterial pneumonia or an ear infection), antibiotics may be prescribed for that specific complication. Over-the-counter cough and cold medicines are generally not recommended for young children, so ask your pediatrician before using them.
Prevention: Vaccines and Immunizations
Significant advances in RSV prevention have emerged in recent years, and the options have continued to expand into 2025 and 2026. The CDC and its Advisory Committee on Immunization Practices (ACIP) currently support the following strategies. Because recommendations are updated periodically, confirm the current guidance with your clinician or the CDC website before making decisions.
- Infant RSV antibodies (nirsevimab/Beyfortus and clesrovimab/Enflonsia): A long-acting monoclonal antibody is recommended for all babies younger than 8 months whose mother did not receive an RSV vaccine during pregnancy, ideally given shortly before or during their first RSV season. Nirsevimab (Beyfortus) has been joined by clesrovimab (Enflonsia), a newer infant antibody. Nirsevimab is also recommended for certain high-risk children ages 8 to 19 months entering their second RSV season. These antibodies provide passive protection for at least about 5 months.
- Maternal RSV vaccine (Abrysvo): Administered to pregnant individuals at 32 to 36 weeks of gestation, generally during September through January in most of the U.S., to pass protective antibodies to the newborn. Protection lasts roughly 6 months after birth. Either the maternal vaccine or an infant antibody is recommended, not routinely both.
- Adult RSV vaccines (Abrysvo, Arexvy, and mResvia): RSV vaccination is recommended for all adults 75 and older, and for adults 50 to 74 who are at increased risk of severe RSV disease. The lower age threshold reflects a 2025 update that expanded eligibility from 60 to 50 for higher-risk adults; a third adult vaccine, Moderna’s mResvia, is also now available alongside Pfizer’s Abrysvo and GSK’s Arexvy. These are generally given as a single dose, and your clinician can advise on timing and whether you need a repeat dose in future seasons.
General prevention measures include frequent handwashing, avoiding close contact with sick individuals, cleaning frequently touched surfaces, and keeping infants away from people with cold symptoms during RSV season. Do not expose infants to secondhand smoke, which significantly increases the risk of severe RSV disease. For broader healthy-habit strategies, see our wellness guide.
Frequently Asked Questions
How long does RSV last?
Mild RSV symptoms typically last 1 to 2 weeks in healthy children and adults. The most severe symptoms usually occur on days 3 to 5 of the illness. Cough may linger for 2 to 4 weeks after other symptoms resolve. Infants who develop bronchiolitis may take 2 to 3 weeks to fully recover.
When should I take my child to the ER for RSV?
Seek emergency care if your child has difficulty breathing (fast breathing, chest retractions, nasal flaring), a bluish tint to the lips or fingernails, pauses in breathing, extreme lethargy, signs of dehydration, or refuses to drink fluids. For infants under 3 months with any fever, or infants of any age who seem to be getting worse rather than better, contact your pediatrician or go to the emergency room without delay.
Can adults get RSV?
Yes. Adults are reinfected with RSV multiple times throughout life. Most healthy adults experience mild cold-like symptoms. However, older adults (65+), adults with chronic heart or lung disease, and immunocompromised individuals can develop severe illness including pneumonia. RSV vaccines are now recommended for adults 75 and older and for adults 50 to 74 at increased risk.
Is RSV contagious?
Yes, RSV is highly contagious. It spreads through respiratory droplets, direct contact, and contaminated surfaces. Infected individuals are typically contagious for 3 to 8 days, though young infants and immunocompromised people may spread the virus for up to 4 weeks. The virus can survive on hard surfaces for several hours.
Is there a vaccine for RSV?
Yes. Several RSV prevention products are now available: monoclonal antibodies for infants (nirsevimab/Beyfortus and clesrovimab/Enflonsia), a maternal vaccine given during pregnancy (Abrysvo), and adult RSV vaccines (Abrysvo, Arexvy, and mResvia) for adults 75 and older and for adults 50 to 74 at increased risk. Recommendations can change from season to season, so talk to your healthcare provider about which options are appropriate for you or your child and verify the latest ACIP guidance.
What to Do Next
If your infant, young child, or elderly family member is showing symptoms of RSV that go beyond a mild cold, particularly difficulty breathing, poor feeding, or unusual lethargy, contact your pediatrician or healthcare provider promptly. Don’t hesitate to go to the emergency room for anyone showing signs of respiratory distress. For prevention, ask your pediatrician about infant antibodies for your baby, discuss the maternal RSV vaccine if you’re pregnant, and talk to your doctor about adult RSV vaccination if you’re 75 or older, or 50 to 74 with risk factors. Early recognition and appropriate preventive measures are the most effective tools against severe RSV disease. This article is for general education only and does not replace personalized advice from a qualified clinician.