Respiratory Syncytial Virus (RSV) is a common respiratory virus that infects the lungs and respiratory tract. It is so common that nearly all children become infected with RSV by age 2. RSV spreads from person to person through the air by coughing and sneezing, direct contact, or touching an object or surface with the virus on it, then touching your mouth, nose, or eyes before washing your hands. Symptoms of RSV infection usually include a runny nose, decrease in appetite, coughing, sneezing, fever, and wheezing. These symptoms usually appear in stages instead of all at once. In very young infants, the only symptoms may be irritability, decreased activity, and trouble breathing. RSV can cause serious lung infections, especially in infants, older adults, and people with serious medical problems. Severe RSV can be unpredictable and is the leading cause of hospitalization in infants. Healthy adults and infants infected with RSV do not usually need to be hospitalized, but some people with RSV infection, especially older adults and infants younger than 6 months of age, may need to be hospitalized. Antiviral medication is not routinely recommended to fight infection, and most RSV infections go away on their own in a week or two.