Overview
Leading cause of bronchiolitis and pneumonia in infants and significant respiratory illness in elderly adults, with new vaccines and monoclonal antibodies available.
Overview
RSV (respiratory syncytial virus) is a common respiratory virus and the leading cause of bronchiolitis and pneumonia in infants under 1 year. It also causes significant respiratory illness in older adults. New vaccines and monoclonal antibody prophylaxis are now available.
Overview
RSV infects nearly all children by age 2. Most cases are mild upper respiratory infections, but the virus can cause severe lower respiratory tract disease — particularly in premature infants, young children with underlying conditions, and adults over 60.\n\nRSV shows seasonal peaks in autumn and winter in temperate climates. Since 2023, new prevention tools have become available: vaccines for older adults and pregnant women, and a monoclonal antibody (nirsevimab) for infant protection. RSV is the most common cause of hospitalization in infants under 1 year.
Emergency Signs
- rapid or labored breathing in infants with visible chest retractions\n- nasal flaring with each breath\n- bluish color of lips, fingernails, or skin (cyanosis)\n- apnea episodes (pauses in breathing) in young infants\n- inability to feed or marked decrease in wet diapers (dehydration)\n- lethargy or unusual irritability
Detailed Symptoms
Most common signs and symptoms
Mild infection: Runny nose, cough, low-grade fever, similar to a common cold. Most cases in healthy older children and adults follow this pattern.\n\nSevere infection (infants): Bronchiolitis with wheezing, rapid or labored breathing, chest retractions (skin pulling in between ribs), bluish skin color, poor feeding, and apnea (breathing pauses) in very young infants.\n\nOlder adults: Cough, fever, wheezing, pneumonia. May worsen underlying heart or lung disease.
Knowing the symptoms is the first step to a quick response.
Course of Disease
Incubation period is 2–8 days. Upper respiratory symptoms appear first and last 1–3 days. Peak illness occurs on days 3–5. Most uncomplicated cases recover within 1–2 weeks. Cough may persist for 2–4 weeks after the acute illness. Viral shedding typically lasts 3–8 days but can be prolonged in immunocompromised individuals.
Diagnosis
How this disease is identified
Rapid antigen detection tests from nasal swab samples are widely available. Molecular testing (RT-PCR) offers higher sensitivity. Clinical diagnosis is often sufficient during typical seasonal outbreaks when an infant presents with characteristic bronchiolitis. Chest X-ray may show hyperinflation and patchy infiltrates in pneumonia.
Treatment
Available treatment methods
Treatment is primarily supportive. For infants: supplemental oxygen, nasal suctioning to clear airways, intravenous fluids if feeding is inadequate, and mechanical ventilation in severe cases. No specific antiviral is approved for routine RSV treatment. For adults: supportive care with bronchodilators and oxygen as needed. Seek medical attention if breathing becomes difficult or feeding decreases significantly in infants.
Most cases are effectively treated with early diagnosis.
Prevention Details
How to protect yourself
- frequent hand washing and avoiding close contact with sick individuals\n- nirsevimab (Beyfortus) — monoclonal antibody recommended for all infants entering their first RSV season\n- RSV vaccines: Arexvy (GSK) and Abrysvo (Pfizer) approved for adults aged 60 and older\n- maternal RSV vaccination (Abrysvo) during pregnancy to protect newborns through transferred antibodies\n- keep high-risk infants away from crowds during peak RSV season
Preparation is the best protection.
Travel Advice
- RSV is not a travel-specific risk, but awareness is important during seasonal peaks\n- practice frequent hand washing and avoid close contact with sick individuals\n- premature infants and high-risk adults traveling during RSV season should discuss preventive options with their physician\n- carry hand sanitizer and avoid crowded enclosed spaces when traveling with high-risk infants
How common is it?
Statistics and geographic data
RSV is a global pathogen causing universal childhood infection. In temperate climates, seasonal epidemics occur from October to March (Northern Hemisphere). Worldwide, RSV causes approximately 33 million lower respiratory infections and 100,000–200,000 deaths annually in children under 5, with the vast majority of deaths occurring in low-income countries with limited access to supportive care.
Risk Factors
Who is most at risk
- age under 6 months (highest risk for severe disease)\n- premature birth (especially before 29 weeks)\n- chronic lung disease of prematurity\n- congenital heart disease\n- immunodeficiency\n- age over 60 years\n- living in congregate settings (nursing homes)\n- daycare attendance increases exposure in young children
Complications Details
Potential complications
Bronchiolitis and viral pneumonia are the most common severe complications. Respiratory failure may require mechanical ventilation in severe cases. Recurrent wheezing episodes can occur in the years following severe RSV infection in infancy. Other complications include otitis media (middle ear infection), secondary bacterial infection, apnea in very young infants, and rarely myocarditis (heart inflammation).
Recovery & Outlook
Expected outcomes and recovery
Most healthy children recover fully within 1–2 weeks. Approximately 2–3% of infants require hospitalization. Mortality is less than 0.5% in developed countries with access to supportive care, but higher in premature infants and those with underlying conditions. In hospitalized elderly adults, mortality reaches 6–8%. Long-term outcomes are generally good with appropriate care.