A highly contagious virus that can cause pneumonia in children is far more common than previously believed, a study shows.
Respiratory syncytial virus, or RSV, sends 2.1 million children under age 5 to the doctor or hospital each year, according to a study of more than 5,000 youngsters in today's New England Journal of Medicine.
In the study, 20% of children hospitalized for respiratory symptoms -- such as coughing and wheezing -- had RSV, along with 18% of the children with these symptoms who went to the emergency room. Hospitalization rates for RSV were three times higher than those for influenza or influenza-like viruses.
"This shows, in a definitive way, that this is a much larger problem," says William Schaffner of Vanderbilt University School of Medicine, who was not involved in the study. "It rivals and exceeds influenza in some populations."
Doctors have known for years that RSV poses a serious risk to premature and very sickly babies, says study author Caroline Breese Hall of the University of Rochester School of Medicine and Dentistry in New York.
Doctors try to prevent the illness by treating these high-risk newborns with antibodies that strengthen their immune system. Those antibodies are too expensive and difficult to give to everyone, she says.
But most of the children with RSV in the study were healthy, with no other medical problems, Hall says. The virus is most common from late fall through early spring. As with cold viruses, people can catch RSV again and again. Newborns, whose immune systems have no experience fighting off the virus, are the most vulnerable.
Each year, about 17 out of 1,000 children under 6 months are hospitalized for RSV, compared with three out of 1,000 children under age 5, the study shows.
None of the children in her study died, but nearly all had a cough, and most had a fever, labored breathing and wheezing, the study says.
Schaffner says he hopes that the finding will speed the creation of a vaccine, which is already under development.
People can protect themselves and their children by washing their hands frequently, he says.
Parents also can protect their babies by keeping their environments smoke-free and by breast-feeding, which allows mothers to pass on germ-fighting antibodies, Schaffner says. Although breast-fed babies may still contract RSV, they typically get a milder case with fewer serious complications.
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