In healthy adults and older children, it is usually a mild respiratory illness. Although studies have shown that people produce antibody against the virus, infections continue to occur in people of all ages.
Symptoms are variable and differ with age.
Infants less than one year old are most severely affected and often have the most trouble breathing . A mild infection often resolves without treatment. A severe infection in infants and children may require hospitalization to provide supplemental oxygen, humidified air, and hydration by intravenous fluids. Aerosol ribavirin , an antiviral medication, may be administered to infants. Ribavirin is not used in older children.