To start with, Kamryn was born seven weeks premature. She spent nearly a month in a neonatal intensive care unit to help her lungs develop. Two weeks after being released, she was rushed back to the hospital in an ambulance, struggling to breathe.

"She turned gray and she wasn't breathing at all," recalls her mother, Stephanie Campbell of Cumming, Georgia

This is the time of year when doctors' offices around the country see more tiny patients with the symptoms of RSV.

The American Academy of Pediatrics reports almost all children are infected with RSV at least once before they turn higiene intima mujer two years of age. Most of the time, the virus causes cold-like symptoms and no specific treatment is needed. For others, the infection is more dangerous.

Lesnick estimates one in 300 normal term babies will be hospitalized each year because of RSV. Premature infants fall into the high-risk category because of their underdeveloped lungs and difficulty in fighting infection. About one of every 30 preemies with RSV requires hospitalization.