Human respiratory syncytial virus (RSV) is a single‑stranded, negative‑sense RNA virus that infects the respiratory tract. It is a leading cause of both upper and lower respiratory infections, especially in infants and young children, and frequently leads to medical visits and hospital admissions in that age group.
How RSV affects people
In infants and toddlers RSV commonly produces bronchiolitis and pneumonia, while older children and adults more often have symptoms of an upper respiratory illness. In very young infants, RSV can cause difficulty breathing, low oxygen levels or pauses in breathing (apnea). Older adults and people with weakened immune systems are also at increased risk of severe disease.
Signs and symptoms
- Runny nose, nasal congestion and cough
- Wheezing and labored breathing
- Fever (may be absent in very young infants)
- Poor feeding or reduced activity in infants
Transmission and seasonality
RSV spreads mainly through respiratory droplets and close personal contact, and can survive for hours on surfaces and hands. In temperate regions, seasonal epidemics typically occur in autumn and winter, although timing and intensity vary by location.
Prevention
Basic measures to reduce spread include hand hygiene, avoiding close contact with sick individuals, and cleaning contaminated surfaces. For infants at high risk of severe RSV illness, there are medical preventive options: long‑acting monoclonal antibodies and, in some settings, maternal vaccination given during pregnancy to protect newborns. Use of these interventions follows national recommendations and is targeted by risk factors such as prematurity or certain chronic conditions.
Treatment and outlook
Treatment is mainly supportive: maintaining hydration, relieving fever, and providing oxygen when needed. Most children recover fully within one to two weeks, but severe cases may require hospital care, including ventilatory support. Specific antiviral treatments are limited and are not routinely used for most patients.