Causes of Respiratory Syncytial Virus
Respiratory syncytial virus enters the body through the eyes, nose or mouth. It spreads easily through the air on infected respiratory droplets. You or your child can become infected if someone with RSV coughs or sneezes near you. The virus also passes to others through direct contact, such as shaking hands.

The virus can live for hours on hard objects such as countertops, crib rails and toys. Touch your mouth, nose or eyes after touching a contaminated object and you're likely to pick up the virus.

An infected person is most contagious in the first few days after infection. However, the virus may continue to spread for up to a few weeks.

Risk factors
By age 2, most children will have been infected with respiratory syncytial virus. Children who attend child care centers or who have siblings who attend school are at a higher risk of exposure. RSV season - when outbreaks tend to occur - is the fall to the end of spring.

People at increased risk of severe or sometimes life-threatening RSV infections include:

Premature infants

Young children who have congenital heart or lung disease

Children with weakened immune systems, such as those undergoing chemotherapy or transplantation

Infants in crowded child care settings

Older adults

Adults with asthma, congestive heart failure or chronic obstructive pulmonary disease

People with immunodeficiency, including those with certain transplanted organs, leukemia or HIV/AIDS