Influenza, particularly H1N1, has understandably captured the attention of public health officials, the media and the public. However, an analysis from Children's Hospital Boston, based on patients seen in its emergency department (ED) during several recent flu seasons, shows that another virus - respiratory syncytial virus (RSV) - takes a substantially greater disease toll among young children than does seasonal flu.
Although the data come from the pre-H1N1 influenza era, the analysis, published online by the journal Pediatrics on November 23, is a reminder that RSV can cause serious illness in infants and young children. Prior studies have shown that by 3 years of age, nearly 100 percent of children are infected with RSV. According to the CDC, RSV is the most common cause of bronchiolitis and pneumonia in children under 1 year of age in the U.S.
The study, led by Florence Bourgeois, MD, MPH and Kenneth Mandl, MD, MPH, both of Children's Division of Emergency Medicine and the Children's Hospital Informatics Program, looked at acute respiratory illnesses in children aged 7 and younger, and found that patients infected with RSV had more than twice as many ED visits and six times more hospitalizations than those infected with seasonal flu. RSV-related illnesses were also twice as likely to lead to additional primary care clinic visits and to antibiotic treatment. The parents of children with RSV missed almost three times more workdays than parents of children with the flu, and parents of children under age 2 were nearly five times more likely to miss work when their child had RSV.
"RSV has been underappreciated," says Bourgeois, who is also affiliated with Harvard Medical School. "There's been disproportionate attention given to influenza, even though our data show morbidity to be very high from RSV. Based on our data, much more should be done in terms of prevention."
The RSV season begins in October, but generally doesn't peak until January and lasts through April/May, so it will become more visible in the coming months, she adds.
Bourgeois and colleagues prospectively studied children aged 7 and under visiting the Children's Hospital Boston ED with acute respiratory illnesses during five consecutive seasons (2001-2006) - an average of 5,288 visits each year. A subgroup of children underwent viral testing; 23.6 percent were found to have RSV and 11.2 percent had influenza. To quantify additional healthcare visits and missed school and work days, the researchers conducted standardized interviews with 210 parents whose children had documented RSV or flu.